Heterocyclic compounds for the inhibition of PASK

ABSTRACT

Disclosed herein are new heterocyclic compounds and compositions and their application as pharmaceuticals for the treatment of disease. Methods of inhibiting PAS Kinase (PASK) activity in a human or animal subject are also provided for the treatment of diseases such as diabetes mellitus.

This application is a bypass continuation application claiming priorityto parent application no. PCT/US2010/047736, filed Sep. 2, 2010, whichclaims the benefit of priority of U.S. Provisional Applications No.61/239,744, filed Sep. 3, 2009, the disclosures of which are herebyincorporated by reference as if written herein in their entireties.

Disclosed herein are new heterocyclic compounds and compositions andtheir application as pharmaceuticals for the treatment of disease.Methods of inhibiting PAS Kinase (PASK) activity in a human or animalsubject are also provided for the treatment of diseases such as diabetesmellitus.

The regulation of glycogen metabolism is critical for the maintenance ofglucose and energy homeostasis in mammals. Glycogen, a large branchedpolymer of glucose, acts as a reserve of carbon and energy in a varietyof organisms. In mammals, the most important stores are found in theliver and skeletal muscle (1). Liver glycogen is required to efficientlybuffer blood glucose levels during fasting, whereas muscle glycogen isprimarily used locally as a fuel for muscle contraction (2).Dysregulation of glycogen metabolism has been implicated in thedevelopment of many diseases, including type 2 diabetes mellitus (3, 4).

The synthesis of glycogen is primarily controlled through regulation ofthe enzyme glycogen synthase (GYS, various isoforms), which catalyzesbulk glycogen synthesis (5, 6, 7). The muscle isoform of glycogensynthase (GYS1) is inactivated by reversible phosphorylation that occursat nine distinct sites within the enzyme (8, 9, 10). In the bestcharacterized form of glycogen synthase, the phosphorylation sites areclustered at the N and C termini (14). Glycogen synthase kinase-3(GSK-3), an insulin-dependent kinase which has long been implicated inthe stepwise phosphorylation of four key sites in the C terminus ofglycogen synthase including Ser-640 (one of the most importantendogenous regulatory phosphorylation sites in mammalian glycogensynthase (15, 32) and Ser-644 (10, 11-13, 24, 25). GSK-3, however, isnot the sole kinase that phosphorylates C-terminal regulatory sites;GSK-3-independent mechanisms also exist, since serine-to-alaninesubstitutions at Ser-7 and Ser-10 block GSK-3-mediated phosphorylationof the important regulatory sites Ser-640 and Ser-644, andphosphorylation at these sites still occurs. PASK (purine-analogsensitive kinase, PAS kinase) is a PAS domain-containingserine/threonine kinase, and genetic experiments in S. cerevisiae yeasthave implicated PASK as a physiological regulator of glycogen synthaseand glycogen accumulation (16, 17). As with the entire glycogen synthaseregulatory system, PASK is highly conserved from yeast to man. HumanPASK (hPASK) phosphorylates glycogen synthase primarily at Ser-640,causing near complete inactivation. It is interesting to note that theexact site of PASK-dependent phosphorylation is similar but notidentical in yeast and mammalian glycogen synthase (18, 19); yeast PASKphosphorylates glycogen synthase at the site analogous to Ser-644, fourresidues C-terminal (18). It appears that the hPASK mid region (residues444-955) is required for efficient phosphorylation of glycogen synthasein vitro and for interaction with glycogen synthase in cells: an hPASKmutant (Δ955) lacking the noncatalytic N terminus was unable toefficiently phosphorylate glycogen synthase. Since this region is notrequired for the phosphorylation of generic, nonphysiologicalsubstrates, such as histones and synthetic peptides, it has beenproposed that the mid region of hPASK is essential forsubstrate-targeting. A similar substrate region has been discovered inmany protein kinases (26-29). Unlike GSK-3, the activity of hPASK hasbeen shown to be independent of insulin and probably regulated insteadby a more direct metabolic signal (23).

Genetic and proteomic screens using yeast PASK identified a number ofsubstrates and implicated this kinase in the regulation of carbohydratemetabolism and translation (18). It has previously been shown that yeastPASK phosphorylates glycogen synthase in vitro and that strains lackingthe PASK genes (PSK1 and PSK2) had elevated glycogen synthase activityand an approximately 5- to 10-fold accumulation of glycogen relative towild-type strains, consistent with impaired ability to phosphorylateglycogen synthase in vivo (18). Because glycogen synthesis andtranslation are two processes tightly regulated in response to nutrientavailability and because PAS domains are frequently involved inmetabolic sensing, a role for PASK in the cellular response to metabolicstatus has been proposed. Indeed, it was recently demonstrated thatmammalian PASK plays a role in the cellular response to nutrients. Thecatalytic activity of PASK in pancreatic islet β-cells is rapidlyincreased in response to glucose addition, and PASK is required for theglucose-responsive expression of some β-cell genes, includingpreproinsulin (23).

PASK catalytic activity is not responsive to glucose alone, however. Theinteraction between the hPASK midregion and glycogen synthase isregulated by at least two factors. First, the PAS domain of PAS kinaseplays a negative role in regulating this interaction. If the PAS domainis deleted or disrupted, hPASK associates more stably with glycogensynthase. PAS domain function is usually controlled by the metabolicstatus of the host cell, as has been suggested for the PASK PAS domain(23). This observation raises the intriguing possibility that thehPASK-glycogen synthase interaction is regulated by the metabolic statusof the cell, thereby enabling an additional layer of metabolicregulation of glycogen synthesis. Second, glycogen negatively regulatesthe hPASK-glycogen synthase interaction, which would initially seemcounterintuitive, since glycogen would thereby stimulate its owncontinued synthesis. It is possible, however, that this mechanism existsto spatially coordinate the synthesis of glycogen. It is becomingincreasingly apparent that glycogen is synthesized in cells in a highlyorganized spatial pattern (30). Perhaps one function of hPASK is tomaintain free, unlocalized glycogen synthase in a phosphorylated,inactive form until it is properly localized to an existing, properlyorganized glycogen particle. These data strongly suggest that the hPASKmidregion plays an important role in targeting hPASK catalytic activityto specific substrates within the cell.

Since hPASK has been recently implicated in glucose-sensing andglucose-responsive transcription, it appears likely that glucosesignaling by means of hPASK affects glycogen metabolism in vivo. It iswell-established that derangement in glycogen metabolism is one of thehallmarks of both Type 1 and Type 2 diabetes (20) and related conditions(21), including a panoply of life-threatening cardiovascular conditions(22). Using PASK1 mice, it has further been demonstrated that PASK isindeed required for normal insulin secretion by pancreatic β cells, andthat PASK deletion results in nearly complete resistance to thephenotypes caused by a high-fat diet, including obesity, insulinresistance and hepatic fat accumulation. Therefore, PASK inhibitionwould comprise a system for the metabolic control of glucose utilizationand storage in mammalian cells, and offer a new method to treatmetabolic diseases including but not limited to diabetes and itscomplications, the metabolic syndrome, insulin resistance, and variouscardiovascular conditions.

The hallmarks of cancer, cellular overgrowth and hyperproliferation,require the rapid synthesis of all cellular materials, including proteinand lipids. Both of these synthetic processes are controlled, to someextent, by PASK. As a result of these observations, it is possible thatinhibition of PASK could be a viable therapeutic strategy for manycancers. By preventing the rapid synthesis of proteins and lipids, suchan inhibitor should prevent the rapid and uncontrolled growth anddivision of cells that characterizes many cancers.

Novel compounds and pharmaceutical compositions, certain of which havebeen found to inhibit PASK have been discovered, together with methodsof synthesizing and using the compounds including methods for thetreatment of PASK-mediated diseases in a patient by administering thecompounds.

In certain embodiments of the present invention, a compound hasstructural Formula I:

-   -   or a pharmaceutically acceptable salt, ester, or prodrug        thereof, wherein:    -   X₁ and X₂ are each independently chosen from CH and N;    -   R₁ and R₂ are each independently chosen from alkyl, cycloalkyl,        heterocycloalkyl, aryl, heteroaryl, and NR₅R₆, any of which may        be optionally substituted, with the proviso that at least one of        R₁ or R₂ is NR₅R₆;    -   R₃ is chosen from hydrogen, halogen, trifluoromethyl, hydroxyl,        C₁-C₅ alkyl, and C₁-C₅ alkoxy, any of which may be optionally        substituted;    -   R₄ is chosen from COOR₇, NO₂, CONR₈R₉, CONR₁₀OR₁₁, and        tetrazolyl;    -   R₅ and R₆ are each independently chosen from hydrogen, alkyl,        cycloalkyl, heterocycloalkyl, alkenyl, alkynyl, aryl,        heteroaryl, aralkyl, and heteroaralkyl, any of which may be        optionally substituted; or taken together, R₅ and R₆ may form a        heterocycloalkyl or heteroaryl, either of which may be        optionally substituted;    -   R₇, R₈, R₉, R₁₀, and R₁₁ are each independently chosen from        hydrogen, C₁-C₆ alkyl, aryl, heteroaryl, aralkyl and        heteroaralkyl, any of which may be optionally substituted;    -   R₁₈ and R₁₉ are independently chosen from cycloalkyl,        heterocycloalkyl, aryl, and heteroaryl, any of which may be        optionally substituted; and    -   m and n are each independently an integer from 0 to 2.

Certain compounds disclosed herein may possess useful PASK modulatingactivity, and may be used in the treatment or prophylaxis of a diseaseor condition in which PASK plays an active role. Thus, in broad aspect,certain embodiments also provide pharmaceutical compositions comprisingone or more compounds disclosed herein together with a pharmaceuticallyacceptable carrier, as well as methods of making and using the compoundsand compositions. Certain embodiments provide methods for modulatingPASK. Other embodiments provide methods for treating a PASK-mediateddisorder in a patient in need of such treatment, comprisingadministering to said patient a therapeutically effective amount of acompound or composition according to the present invention. Alsoprovided is the use of certain compounds disclosed herein for use in themanufacture of a medicament for the treatment of a disease or conditionameliorated by the inhibition of PASK.

In certain embodiments of the present invention, a compound hasstructural Formula I:

-   -   or a pharmaceutically acceptable salt, ester, or prodrug        thereof, wherein:    -   X₁ and X₂ are each independently chosen from CH and N;    -   R₁ and R₂ are each independently chosen from alkyl, cycloalkyl,        heterocycloalkyl, aryl, heteroaryl, and NR₅R₆, any of which may        be optionally substituted, with the proviso that at least one of        R₁ or R₂ is NR₅R₆;    -   R₃ is chosen from hydrogen, halogen, trifluoromethyl, hydroxyl,        C₁-C₅ alkyl, and C₁-C₅ alkoxy, any of which may be optionally        substituted;    -   R₄ is chosen from COOR₇, NO₂, CONR₈R₉, CONR₁₀OR₁₁, and        tetrazolyl;    -   R₅ and R₆ are each independently chosen from hydrogen, C₁-C₆        alkyl, C₁-C₇ cycloalkyl, C₁-C₇ heterocycloalkyl, C₁-C₆ alkenyl,        C₁-C₆ alkynyl, aryl, heteroaryl, aralkyl, and heteroaralkyl, any        of which may be optionally substituted; or taken together, R₅        and R₆ may form a heterocycloalkyl or heteroaryl, either of        which may be optionally substituted;    -   R₇, R₈, R₉, R₁₀, and R₁₁ are each independently chosen from        hydrogen, C₁-C₆ alkyl, aryl, heteroaryl, aralkyl and        heteroaralkyl, any of which may be optionally substituted;    -   R₁₈ and R₁₉ are independently chosen from cycloalkyl,        heterocycloalkyl, aryl, and heteroaryl, any of which may be        optionally substituted; and    -   m and n are each independently an integer from 0 to 2.

In certain embodiments compounds of Formula I are provided wherein X₁and X₂ are N.

In certain embodiments compounds of Formula I are provided wherein R₄ isCOOR₇.

In certain embodiments compounds of Formula I are provided wherein

-   -   R₁ is chosen from alkyl, phenyl and heteroaryl, and has one or        more substituents chosen from hydrogen, halo, alkyl, alkenyl,        alkynyl, cycloalkyl, haloalkyl, aryl, aralkyl, heterocyclyl,        heteroaryl, heterarylalkyl, CN, alkoxy, alkylamino,        dialkylamino, NHSO₂R₁₂, NHSO₂NHR₁₂, NHCOR₁₂, NHCONHR₁₂, CONHR₁₂,        CONR_(12a)R_(12b), hydroxy and OCF₃; and    -   R₁₂, R_(12a) and R_(12b) are independently chosen from hydrogen,        C₁-C₆ alkyl, aryl, heteroaryl, aralkyl and heteroaralkyl, any of        which may be optionally substituted.

In certain embodiments compounds of Formula I are provided wherein

-   -   R₂ is chosen from phenyl and heteroaryl and has one or more        substituents selected from the following group: hydrogen, halo,        alkyl, alkenyl, alkynyl, cycloalkyl, haloalkyl, aryl, aralkyl,        heterocyclyl, heteroaryl, heterarylalkyl, CN, alkoxy,        alkylamino, dialkylamino, NHSO₂R₁₃, NHSO₂NHR₁₃, NHCOR₁₃,        NHCONHR₁₃, CONHR₁₃, CONR_(13a)R_(13b), hydroxy and OCF₃; and    -   R₁₃, R_(13a) and R_(13b) are independently chosen from hydrogen,        C₁-C₆ alkyl, aryl, heteroaryl, aralkyl and heteroaralkyl, any of        which may be optionally substituted.

In certain embodiments compounds of Formula I are provided wherein R₁₈and R₁₉ are optionally substituted with one or more substituents chosenfrom hydrogen, halogen, alkoxy, haloalkoxy, alkyl, and amino.

In certain embodiments compounds of Formula I are provided wherein R₇ ishydrogen.

In certain embodiments compounds of Formula I are provided wherein m is0.

In certain embodiments compounds of Formula I are provided wherein n is0.

In certain embodiments of the present invention, a compound hasstructural Formula II:

-   -   or a salt, ester or prodrug thereof, wherein:    -   R₂ is chosen from alkyl, aryl and heteroaryl, any of which may        be optionally substituted with one or more substituents chosen        from hydrogen, halo, alkyl, alkenyl, alkynyl, cycloalkyl,        haloalkyl, aryl, aralkyl, heterocyclyl, heteroaryl,        heterarylalkyl, CN, alkoxy, alkylamino, dialkylamino, NHSO₂R₁₃,        NHSO₂NHR₁₃, NHCOR₁₃, NHCONHR₁₃, CONHR₁₃, CONR_(13a)R_(13b),        hydroxy, and OCF₃;    -   R₃ is chosen from hydrogen, hydroxyl, C₁-C₅ alkyl, and C₁-C₅        alkoxy, any of which may be optionally substituted;    -   R₁₄ and R₁₅ are independently chosen from hydrogen, C₁-C₆ alkyl,        aryl, heteroaryl, aralkyl, and heteroaralkyl, or taken together,        R₁₄ and R₁₅ may form a heterocycloalkyl, any of which may be        optionally substituted; and    -   R₁₃, R_(13a) and R_(13b) are independently chosen from hydrogen,        C₁-C₆ alkyl, aryl, heteroaryl, aralkyl and heteroaralkyl, any of        which may be optionally substituted.

In certain embodiments of the present invention, a compound hasstructural Formula III:

-   -   or a salt, ester or prodrug thereof, wherein:    -   R₂ is chosen from alkyl, aryl and heteroaryl, any of which may        be optionally substituted with one or more substituents chosen        from hydrogen, halo, alkyl, alkenyl, alkynyl, cycloalkyl,        haloalkyl, aryl, aralkyl, heterocyclyl, heteroaryl,        heterarylalkyl, CN, alkoxy, alkylamino, dialkylamino, NHSO₂R₁₃,        NHSO₂NHR₁₃, NHCOR₁₃, NHCONHR₁₃, CONHR₁₃, CONR_(13a)R_(13b),        hydroxy, and OCF₃;    -   R₃ is chosen from hydrogen and hydroxyl;    -   R₁₃, R_(13a) and R_(13b) are independently chosen from hydrogen,        C₁-C₆ alkyl, aryl, heteroaryl, aralkyl and heteroaralkyl, any of        which may be optionally substituted;    -   R₁₇ is chosen from null, hydrogen, alkyl, cycloalkyl,        heterocycloalkyl, aryl, and heteroaryl, any of which may be        optionally substituted; and    -   X₄ is chosen from CH, N, and O.

In certain embodiments of the present invention, a compound hasstructural Formula IV:

-   -   or a salt, ester or prodrug thereof, wherein:    -   Rz is chosen from OH, NR₈, R₉, NR₈OR₉;    -   R₁ is chosen from aryl and heteroaryl, either of which may be        optionally substituted with one or more substituents chosen from        hydrogen, halo, alkyl, alkenyl, alkynyl, cycloalkyl, haloalkyl,        aryl, aralkyl, heterocyclyl, heteroaryl, heterarylalkyl, CN,        alkoxy, alkylamino, dialkylamino, NHSO₂R₁₂, NHSO₂NHR₁₂, NHCOR₁₂,        NHCONHR₁₂, CONHR₁₂, CONR_(12a)R_(12b), hydroxy, SO₂R₁₂,        SO₂NHR₁₂, CF₃, and OCF₃;    -   R₃ is chosen from hydrogen, hydroxyl, C₁-C₅ alkyl, and C₁-C₅        alkoxy, any of which may be optionally substituted;    -   R₅ and R₆ are independently chosen from hydrogen, C₁-C₆ alkyl,        C₁-C₇ cycloalkyl, C₁-C₇ heterocycloalkyl, C₁-C₆ alkenyl, C₁-C₆        alkynyl, aryl, heteroaryl, aralkyl, and heteroaralkyl, or taken        together, R₅ and R₆ may form a heterocycloalkyl or heteroaryl,        any of which may be optionally substituted;    -   R₈ and R₉ are each independently chosen from hydrogen, C₁-C₆        alkyl, aryl, heteroaryl, aralkyl and heteroaralkyl, any of which        may be optionally substituted; and    -   R₁₂, R_(12a) and R_(12b) are independently chosen from hydrogen,        C₁-C₆ alkyl, aryl, heteroaryl, aralkyl, CF₃ and heteroaralkyl,        any of which may be optionally substituted.

In certain embodiments compounds of Formula IV are provided wherein

-   -   R₁ is phenyl and has one or more substituents chosen from        hydrogen, halo, alkyl, alkenyl, alkynyl, cycloalkyl, haloalkyl,        aryl, aralkyl, heterocyclyl, heteroaryl, heterarylalkyl, CN,        alkoxy, alkylamino, dialkylamino, NHSO₂R₁₂, NHSO₂NHR₁₂, NHCOR₁₂,        NHCONHR₁₂, CONHR₁₂, CONR_(12a)R_(12b), hydroxy and OCF₃; and    -   R₁₂, R_(12a) and R_(12b) are independently chosen from hydrogen,        C₁-C₆ alkyl, aryl, heteroaryl, aralkyl and heteroaralkyl, any of        which may be optionally substituted.

In certain embodiments compounds of Formula IV are provided wherein R₅and R₆ are independently C₁-C₆ alkyl.

In certain embodiments compounds of Formula IV are provided wherein R₃is hydrogen.

In certain embodiments R₅ and R₆ are independently C₁-C₆ alkyl.

In certain embodiments of the present invention, a compound hasstructural Formula V:

-   -   or a salt, ester or prodrug thereof, wherein:    -   R₁ is chosen from aryl and heteroaryl, either of which may be        optionally substituted with one or more substituents chosen from        hydrogen, halo, alkyl, alkenyl, alkynyl, cycloalkyl, haloalkyl,        aryl, aralkyl, heterocyclyl, heteroaryl, heterarylalkyl, CN,        alkoxy, alkylamino, dialkylamino, NHSO₂R₁₂, NHSO₂NHR₁₂, NHCOR₁₂,        NHCONHR₁₂, CONHR₁₂, CONR_(12a)R_(12b), hydroxy, CF₃, SO₂R₁₂,        NHSO₂R₁₂, and OCF₃;    -   R₃ is chosen from hydrogen and hydroxyl;    -   R₁₂, R_(12a) and R_(12b) are independently chosen from hydrogen,        C₁-C₆ alkyl, aryl, heteroaryl, aralkyl and heteroaralkyl, any of        which may be optionally substituted;    -   R₁₆ is chosen from null, hydrogen, alkyl, cycloalkyl,        heterocycloalkyl, aryl, and heteroaryl any of which may be        optionally substituted;    -   R₁₇ is chosen from hydrogen and C₁-C₆ alkyl; and    -   X₃ is chosen from CH, N, and O.

In certain embodiments of the present invention, a compound hasstructural Formula VI:

-   -   or a salt, ester or prodrug thereof, wherein:    -   Rz is chosen from OH, NR₈, R₉, NR₈OR₉;    -   R₁ is chosen from aryl and heteroaryl, either of which may be        optionally substituted with one or more substituents chosen from        hydrogen, halo, alkyl, alkenyl, alkynyl, cycloalkyl, haloalkyl,        aryl, aralkyl, heterocyclyl, heteroaryl, heterarylalkyl, CN,        alkoxy, alkylamino, dialkylamino, NHSO₂R₁₂, NHSO₂NHR₁₂, NHCOR₁₂,        NHCONHR₁₂, CONHR₁₂, CONR_(12a)R_(12b), hydroxy, and CF₃, SO₂R₁₂,        SO₂NHR₁₂, SO₂NR_(12a)R_(12b), COOH, and OCF₃;    -   R₃ is chosen from hydrogen and hydroxyl;    -   R₈ and R₉ are each independently chosen from hydrogen, C₁-C₆        alkyl, aryl, heteroaryl, aralkyl and heteroaralkyl, any of which        may be optionally substituted;    -   R₁₂, R_(12a) and R_(12b) are independently chosen from hydrogen,        C₁-C₆ alkyl, aryl, heteroaryl, aralkyl and heteroaralkyl, any of        which may be optionally substituted;    -   R₁₉ is chosen from null, hydrogen, alkyl, alkoxy, CF₃, OCF₃,        COOH, halo, alkenyl, alkynyl, hydroxy, alkyllsulfonyl, cyano,        nitro, alkylamino, dialkylamino, NHSO₂R₁₂, NHSO₂NHR₁₂, NHCOR₁₂,        NHCONHR₁₂, CONR_(12a)R_(12b), aryl, and heteroaryl;    -   n is an integer from 0 to 3; and    -   X₃ is chosen from CH₂, NR₁₂, S, SO₂, and O.

Further provided is a compound as recited in Claim 1 for use as amedicament.

Further provided is a compound as recited in Claim 1 for use in themanufacture of a medicament for the prevention or treatment of a diseaseor condition ameliorated by the inhibition of PASK.

Further provided is a compound as disclosed herein for use in themanufacture of a medicament for the prevention or treatment of a diseaseor condition ameliorated by the inhibition of PASK.

Further provided is a compound chosen from

-   2-phenyl-3-(4-(4-(trifluoromethyl)phenyl)piperazin-1-yl)quinoxaline-6-carboxylic    acid,-   2-phenyl-3-(4-(4-(trifluoromethyl)phenyl)piperazin-1-yl)quinoxaline-6-carboxylic    acid,-   3-(4-(3-chlorophenyl)piperazin-1-yl)-2-phenylquinoxaline-6-carboxylic    acid,-   3-(4-methylpiperazin-1-yl)-2-phenylquinoxaline-6-carboxylic acid,-   2-phenyl-3-(piperazin-1-yl)quinoxaline-6-carboxylic acid,-   2-phenyl-3-(4-phenylpiperazin-1-yl)quinoxaline-6-carboxylic acid,-   2-phenyl-3-(4-(4-(trifluoromethyl)phenyl)piperidin-1-yl)quinoxaline-6-carboxylic    acid,-   3-(4-(4-chlorophenyl)piperazin-1-yl)-2-phenylquinoxaline-6-carboxylic    acid,-   3-(4-(4-methoxyphenyl)piperazin-1-yl)-2-phenylquinoxaline-6-carboxylic    acid,-   3-(4-(3-chlorophenyl)piperidin-1-yl)-2-phenylquinoxaline-6-carboxylic    acid,-   3-(4-(4-methoxyphenyl)piperidin-1-yl)-2-phenylquinoxaline-6-carboxylic    acid,-   2-phenyl-3-(piperidin-1-yl)quinoxaline-6-carboxylic acid,-   2-phenyl-3-(4-phenylpiperidin-1-yl)quinoxaline-6-carboxylic acid,-   3-(azepan-1-yl)-2-phenylquinoxaline-6-carboxylic acid,-   3-(4-(4-chlorophenyl)piperidin-1-yl)-2-phenylquinoxaline-6-carboxylic    acid,-   3-morpholino-2-phenylquinoxaline-6-carboxylic acid,-   3-(4-methyl-1,4-diazepan-1-yl)-2-phenylquinoxaline-6-carboxylic    acid,-   3-(isopropylamino)-2-phenylquinoxaline-6-carboxylic acid,-   2-phenyl-3-(4-(pyrimidin-2-yl)piperazin-1-yl)quinoxaline-6-carboxylic    acid,-   2-phenyl-3-(4-(5-(trifluoromethyl)pyridin-2-yl)piperazin-1-yl)quinoxaline-6-carboxylic    acid,-   2-phenyl-3-(4-(quinolin-2-yl)piperazin-1-yl)quinoxaline-6-carboxylic    acid,-   2-(azepan-1-yl)-3-phenylquinoxaline-6-carboxylic acid,-   3-phenyl-2-(piperidin-1-yl)quinoxaline-6-carboxylic acid,-   2-(4-(4-chlorophenyl)piperidin-1-yl)-3-(4-fluorophenyl)quinoxaline-6-carboxylic    acid,-   2-(4-(3-chlorophenyl)piperidin-1-yl)-3-(4-fluorophenyl)quinoxaline-6-carboxylic    acid,-   3-(4-fluorophenyl)-2-(4-(4-methoxyphenyl)piperidin-1-yl)quinoxaline-6-carboxylic    acid,-   3-(4-fluorophenyl)-2-(4-(pyridin-2-yl)piperazin-1-yl)quinoxaline-6-carboxylic    acid,-   2-phenyl-3-(4-(3-(trifluoromethyl)pyridin-2-yl)piperazin-1-yl)quinoxaline-6-carboxylic    acid,-   3-(4-fluorophenyl)-2-(4-(4-(trifluoromethyl)phenyl)piperidin-1-yl)quinoxaline-6-carboxylic    acid,-   2,3-bis(4-phenylpiperidin-1-yl)quinoxaline-6-carboxylic acid,-   2,3-bis(4-methoxyphenyl)-6-(1H-tetrazol-5-yl)quinoxaline,-   3-(4-(N-methylmethan-3-ylsulfonamido)piperidin-1-yl)-2-phenylquinoxaline-6-carboxylic    acid,-   3-(4-(methylsulfonyl)piperazin-1-yl)-2-phenylquinoxaline-6-carboxylic    acid,-   3-(4-(N-methylacetamido)piperidin-1-yl)-2-phenylquinoxaline-6-carboxylic    acid,-   3-(4-(methyl(phenyl)amino)piperidin-1-yl)-2-phenylquinoxaline-6-carboxylic    acid,-   3-(diethylamino)-2-phenylquinoxaline-6-carboxylic acid,-   3-(N-methylmethan-5-ylsulfonamido)-2-phenylquinoxaline-6-carboxylic    acid,-   3-(3,4-dihydroisoquinolin-2(1H)-yl)-2-phenylquinoxaline-6-carboxylic    acid,-   3-(3,4-dihydroquinolin-1(2H)-yl)-2-phenylquinoxaline-6-carboxylic    acid,-   3-(phenethylamino)-2-phenylquinoxaline-6-carboxylic acid,-   3-(methyl(phenethyl)amino)-2-phenylquinoxaline-6-carboxylic acid,-   3-(isopropyl(methyl)amino)-2-phenylquinoxaline-6-carboxylic acid,-   3-(cyclohexylamino)-2-phenylquinoxaline-6-carboxylic acid,-   3-(2-methylpiperidin-1-yl)-2-phenylquinoxaline-6-carboxylic acid,-   3-(cyclopropyl(methyl)amino)-2-phenylquinoxaline-6-carboxylic acid,-   3-(2-methylpyrrolidin-1-yl)-2-phenylquinoxaline-6-carboxylic acid,-   3-(sec-butyl(methyl)amino)-2-phenylquinoxaline-6-carboxylic acid,-   (R)-3-(3-hydroxypyrrolidin-1-yl)-2-phenylquinoxaline-6-carboxylic    acid,-   (S)-3-(3-hydroxypyrrolidin-1-yl)-2-phenylquinoxaline-6-carboxylic    acid,-   (R)-3-(2-(methoxymethyl)pyrrolidin-1-yl)-2-phenylquinoxaline-6-carboxylic    acid,-   (R)-3-(2-(hydroxymethyl)pyrrolidin-1-yl)-2-phenylquinoxaline-6-carboxylic    acid,-   (S)-3-(2-(hydroxymethyl)pyrrolidin-1-yl)-2-phenylquinoxaline-6-carboxylic    acid,-   3-(3-methylmorpholino)-2-phenylquinoxaline-6-carboxylic acid,-   (S)-3-(2-methylpyrrolidin-1-yl)-2-phenylquinoxaline-6-carboxylic    acid,-   2-(4-fluorophenyl)-3-(isopropyl(methyl)amino)quinoxaline-6-carboxylic    acid,-   3-(isopropyl(methyl)amino)-2-(4-methoxyphenyl)quinoxaline-6-carboxylic    acid,-   (R)-3-(methyl(1-phenylethyl)amino)-2-phenylquinoxaline-6-carboxylic    acid.-   (S)-3-(methyl(1-phenylethyl)amino)-2-phenylquinoxaline-6-carboxylic    acid,-   (R)-3-(sec-butyl(methyl)amino)-2-phenylquinoxaline-6-carboxylic    acid,-   3-(1H-indol-1-yl)-2-phenylquinoxaline-6-carboxylic acid,-   2-(3,4-difluorophenyl)-3-(isopropyl(methyl)amino)quinoxaline-6-carboxylic    acid,-   2-(4-chlorophenyl)-3-(isopropyl(methyl)amino)quinoxaline-6-carboxylic    acid,-   (R)-2-phenyl-3-(2-(trifluoromethyl)pyrrolidin-1-yl)quinoxaline-6-carboxylic    acid,-   3-(6-methoxy-3,4-dihydroquinolin-1(2H)-yl)-2-phenylquinoxaline-6-carboxylic    acid,-   3-(indolin-1-yl)-2-phenylquinoxaline-6-carboxylic acid,-   3-(2,3-dihydrobenzo[b][1,4]oxazin-4-yl)-2-phenylquinoxaline-6-carboxylic    acid,-   3-(isopropyl(methyl)amino)-2-(3-methoxyphenyl)quinoxaline-6-carboxylic    acid,-   2-(3-fluorophenyl)-3-(isopropyl(methyl)amino)quinoxaline-6-carboxylic    acid,-   2-(2-fluorophenyl)-3-(isopropyl(methyl)amino)quinoxaline-6-carboxylic    acid,-   3-(cyclopentyl(methyl)amino)-2-phenylquinoxaline-6-carboxylic acid,-   3-(isopropyl(methyl)amino)-2-(4-methoxyphenyl)quinoxaline-6-carboxylic    acid,-   (S)-2-(4-fluorophenyl)-3-(2-methylpyrrolidin-1-yl)quinoxaline-6-carboxylic    acid,-   butyl    2-(4-fluorophenyl)-3-(piperidin-1-yl)quinoxaline-6-carboxylate,-   3-(azepan-1-yl)-2-(4-fluorophenyl)quinoxaline-6-carboxylic acid,-   2-(benzo[d][1,3]dioxol-5-yl)-3-(isopropyl(methyl)amino)quinoxaline-6-carboxylic    acid,-   2-(4-fluorophenyl)-3-(3-(methoxymethyl)piperidin-1-yl)quinoxaline-6-carboxylic    acid,-   3-(3,3-dimethylpiperidin-1-yl)-2-(4-fluorophenyl)quinoxaline-6-carboxylic    acid,-   2-(4-fluorophenyl)-3-(3-methylpiperidin-1-yl)quinoxaline-6-carboxylic    acid,-   2-(2,3-dihydrobenzo[b][1,4]dioxin-6-yl)-3-(isopropyl(methyl)amino)quinoxaline-6-carboxylic    acid,-   3-(isopropyl(methyl)amino)-2-(4-(methylsulfonyl)phenyl)quinoxaline-6-carboxylic    acid,-   2-(benzo[d][1,3]dioxol-5-yl)-3-((S)-2-methylpyrrolidin-1-yl)quinoxaline-6-carboxylic    acid,-   2-(1H-indol-5-yl)-3-(isopropyl(methyl)amino)quinoxaline-6-carboxylic    acid,-   3-(isopropyl(methyl)amino)-2-(4-(trifluoromethoxy)phenyl)quinoxaline-6-carboxylic    acid,-   2-(4-cyanophenyl)-3-(isopropyl(methyl)amino)quinoxaline-6-carboxylic    acid,-   3-(isopropyl(methyl)amino)-2-(pyridin-4-yl)quinoxaline-6-carboxylic    acid,-   2-(H-imidazo[1,2-a]pyridin-6-yl)-3-(isopropyl(methyl)amino)quinoxaline-6-carboxylic    acid,-   2-(benzofuran-2-yl)-3-(isopropyl(methyl)amino)quinoxaline-6-carboxylic    acid,-   (S)-2-(4-fluorophenyl)-3-(2-methyl-4-(pyridin-2-yl)piperazin-1-yl)quinoxaline-6-carboxylic    acid,-   (S)-2-(4-fluorophenyl)-3-(2-methylpiperidin-1-yl)quinoxaline-6-carboxylic    acid,-   3-(cyclopropyl(methyl)amino)-2-(4-fluorophenyl)quinoxaline-6-carboxylic    acid,-   (R)-2-(4-fluorophenyl)-3-(2-(methoxymethyl)pyrrolidin-1-yl)quinoxaline-6-carboxylic    acid,-   (S)-3-(2-methyl-4-(pyridin-2-yl)piperazin-1-yl)-2-phenylquinoxaline-6-carboxylic    acid,-   2-(benzo[d][1,3]dioxol-5-yl)-3-(3,4-dihydroquinolin-1(2H)-yl)quinoxaline-6-carboxylic    acid,-   3-(octahydroquinolin-1(2H)-yl)-2-phenylquinoxaline-6-carboxylic    acid,-   3-(isopropyl(methyl)amino)-2-(pyridin-3-yl)quinoxaline-6-carboxylic    acid,-   2-(furan-2-yl)-3-(isopropyl(methyl)amino)quinoxaline-6-carboxylic    acid,-   3-(isopropyl(methyl)amino)-2-(quinolin-3-yl)quinoxaline-6-carboxylic    acid,-   3-(isopropyl(methyl)amino)-2-(4-morpholinophenyl)quinoxaline-6-carboxylic    acid,-   3-(1,1-dioxidothiomorpholino)-2-(4-fluorophenyl)quinoxaline-6-carboxylic    acid,-   3-(1,1-dioxidothiomorpholino)-2-phenylquinoxaline-6-carboxylic acid,-   2-(4-fluorophenyl)-3-(3-oxopiperazin-1-yl)quinoxaline-6-carboxylic    acid,-   2-(4-fluorophenyl)-3-(methyl(piperidin-4-yl)amino)quinoxaline-6-carboxylic    acid,-   2-(4-fluorophenyl)-3-(methyl(tetrahydro-2H-pyran-4-yl)amino)quinoxaline-6-carboxylic    acid,-   3-(cyclopentyl(methyl)amino)-2-(4-fluorophenyl)quinoxaline-6-carboxylic    acid,-   3-(isopropyl(methyl)amino)-2-(5-methylthiophen-2-yl)quinoxaline-6-carboxylic    acid,-   3-(isopropyl(methyl)amino)-2-(thiophen-2-yl)quinoxaline-6-carboxylic    acid,-   3-(isopropyl(methyl)amino)-2-(6-methoxypyridin-3-yl)quinoxaline-6-carboxylic    acid,-   2-(furan-2-yl)-3-(isopropyl(methyl)amino)quinoxaline-6-carboxylic    acid,-   2-(4-fluorophenyl)-3-(4-(N-methylacetamido)piperidin-1-yl)quinoxaline-6-carboxylic    acid,-   2-(4-fluorophenyl)-3-(4-methyl-3-oxopiperazin-1-yl)quinoxaline-6-carboxylic    acid,-   3-(4-acetamidopiperidin-1-yl)-2-phenylquinoxaline-6-carboxylic acid,-   2-phenyl-3-(2,3,4,5-tetrahydro-1H-benzo[b]azepin-1-yl)quinoxaline-6-carboxylic    acid,-   2-(4-fluorophenyl)-3-(2,3,4,5-tetrahydro-1H-benzo[b]azepin-1-yl)quinoxaline-6-carboxylic    acid,-   (S)-3-(sec-butyl(methyl)amino)-2-(4-fluorophenyl)quinoxaline-6-carboxylic    acid,-   3-(sec-butyl(methyl)amino)-2-(furan-3-yl)quinoxaline-6-carboxylic    acid,-   3-(isopropyl(methyl)amino)-2-(1H-pyrazol-4-yl)quinoxaline-6-carboxylic    acid,-   3-(isopropyl(methyl)amino)-2-(6-methoxypyridin-3-yl)quinoxaline-6-carboxylic    acid,-   2-(1H-indazol-6-yl)-3-(isopropyl(methyl)amino)quinoxaline-6-carboxylic    acid,-   3-(isopropyl(methyl)amino)-2-(1-methyl-1H-indazol-6-yl)quinoxaline-6-carboxylic    acid,-   2-(1H-indol-6-yl)-3-(isopropyl(methyl)amino)quinoxaline-6-carboxylic    acid,-   2-(1-(tert-butoxycarbonyl)-1H-indol-2-yl)-3-(isopropyl(methyl)amino)quinoxaline-6-carboxylic    acid,-   2-(1H-indol-2-yl)-3-(isopropyl(methyl)amino)quinoxaline-6-carboxylic    acid,-   2-(1-(tert-butoxycarbonyl)-5-methoxy-1H-indol-2-yl)-3-(isopropyl(methyl)amino)quinoxaline-6-carboxylic    acid,-   3-(isopropyl(methyl)amino)-2-(5-methoxy-1H-indol-2-yl)quinoxaline-6-carboxylic    acid,-   2-(5-fluoro-1H-indol-2-yl)-3-(isopropyl(methyl)amino)quinoxaline-6-carboxylic    acid,-   2-(5-bromopyridin-3-yl)-3-(isopropyl(methyl)amino)quinoxaline-6-carboxylic    acid,-   2-(1H-indazol-5-yl)-3-(isopropyl(methyl)amino)quinoxaline-6-carboxylic    acid,-   3-(isopropyl(methyl)amino)-2-(3-(trifluoromethyl)-1H-pyrazol-4-yl)quinoxaline-6-carboxylic    acid,-   2-(6-(tert-butoxycarbonylamino)pyridin-3-yl)-3-(isopropyl(methyl)amino)quinoxaline-6-carboxylic    acid,-   2-(5-fluoropyridin-2-yl)-3-(isopropyl(methyl)amino)quinoxaline-6-carboxylic    acid,-   3-(isopropyl(methyl)amino)-2-(5-(trifluoromethyl)pyridin-2-yl)quinoxaline-6-carboxylic    acid,-   3-(isopropyl(methyl)amino)-2-(6-(trifluoromethyl)pyridin-3-yl)quinoxaline-6-carboxylic    acid,-   2-(5-cyanopyridin-2-yl)-3-(isopropyl(methyl)amino)quinoxaline-6-carboxylic    acid,-   3-(isopropyl(methyl)amino)-2-(6-(pyrrolidin-1-yl)pyridin-3-yl)quinoxaline-6-carboxylic    acid,-   2-(6-fluoropyridin-3-yl)-3-(isopropyl(methyl)amino)quinoxaline-6-carboxylic    acid,-   (S)-2-(benzofuran-2-yl)-3-(2-methylpyrrolidin-1-yl)quinoxaline-6-carboxylic    acid,-   2-(benzofuran-2-yl)-3-(cyclopropyl(methyl)amino)quinoxaline-6-carboxylic    acid,-   2-(5-fluorobenzofuran-2-yl)-3-(isopropyl(methyl)amino)quinoxaline-6-carboxylic    acid,-   2-(5-chlorobenzofuran-2-yl)-3-(isopropyl(methyl)amino)quinoxaline-6-carboxylic    acid, and-   2-(benzofuran-2-yl)-3-(sec-butyl(methyl)amino)quinoxaline-6-carboxylic    acid.

Further provided is a pharmaceutical composition comprising a compoundas recited above together with a pharmaceutically acceptable carrier.

Further provided is a method of inhibiting PASK comprising contactingPASK with a compound as disclosed above.

Further provided is a method of treatment of a disease comprising theadministration of a therapeutically effective amount of a compound asdisclosed above to a patient in need thereof.

Further provided is the method as recited above wherein said disease ischosen from cancer and a metabolic disease.

Further provided is the method as recited above wherein said disease isa metabolic disease.

Further provided is the method as recited above wherein said metabolicdisease is chosen from metabolic syndrome, diabetes, dyslipidemia, fattyliver disease, non-alcoholic steatohepatitis, obesity, and insulinresistance.

Further provided is the method disclosed above wherein said diabetes isType II diabetes.

Further provided is the method as disclosed above wherein saiddyslipidemia is hyperlipidemia.

Further provided is a method for achieving an effect in a patientcomprising the administration of a therapeutically effective amount of acompound as disclosed above to a patient, wherein the effect is selectedfrom the group consisting of reduction of triglycerides, reduction ofcholesterol, and reduction of hemoglobin A1c.

Further provided is the method as disclosed above wherein saidcholesterol is chosen from LDL and VLDL cholesterol.

Further provided is the method as disclosed above wherein saidtriglycerides are chosen from plasma triglycerides and livertriglycerides.

Further provided is a method of treatment of a PASK-mediated diseasecomprising the administration of:

-   -   a. a therapeutically effective amount of a compound as disclosed        above; and    -   b. another therapeutic agent.

Not to be bound by any theory or mechanism, the compounds disclosedherein can be used to treat or modulate metabolic disease (including butnot limited to diabetes, metabolic disorder, dyslipidemia, fatty liverdisease, non-alcoholic steatohepatitis, obesity, and insulin resistance,as well as to reduce triglycerides, cholesterol, and hemoglobin A1c) andcancer.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows change in body weight over time for the Vehicle-, WAY-, andsubject compound-treated rats during the in vivo studies.

As used herein, the terms below have the meanings indicated.

When ranges of values are disclosed, and the notation “from n₁ . . . ton₂” is used, where n₁ and n₂ are the numbers, then unless otherwisespecified, this notation is intended to include the numbers themselvesand the range between them. This range may be integral or continuousbetween and including the end values. By way of example, the range “from2 to 6 carbons” is intended to include two, three, four, five, and sixcarbons, since carbons come in integer units. Compare, by way ofexample, the range “from 1 to 3 μM (micromolar),” which is intended toinclude 1 μM, 3 μM, and everything in between to any number ofsignificant figures (e.g., 1.255 μM, 2.1 μM, 2.9999 μM, etc.).

The term “about,” as used herein, is intended to qualify the numericalvalues which it modifies, denoting such a value as variable within amargin of error. When no particular margin of error, such as a standarddeviation to a mean value given in a chart or table of data, is recited,the term “about” should be understood to mean that range which wouldencompass the recited value and the range which would be included byrounding up or down to that figure as well, taking into accountsignificant figures.

The term “acyl,” as used herein, alone or in combination, refers to acarbonyl attached to an alkenyl, alkyl, aryl, cycloalkyl, heteroaryl,heterocycle, or any other moiety were the atom attached to the carbonylis carbon. An “acetyl” group refers to a —C(O)CH₃ group. An“alkylcarbonyl” or “alkanoyl” group refers to an alkyl group attached tothe parent molecular moiety through a carbonyl group. Examples of suchgroups include methylcarbonyl and ethylcarbonyl. Examples of acyl groupsinclude formyl, alkanoyl and aroyl.

The term “alkenyl,” as used herein, alone or in combination, refers to astraight-chain or branched-chain hydrocarbon radical having one or moredouble bonds and containing from 2 to 20 carbon atoms. In certainembodiments, said alkenyl will comprise from 2 to 6 carbon atoms. Theterm “alkenylene” refers to a carbon-carbon double bond system attachedat two or more positions such as ethenylene [(—CH═CH—), (—C:C—)].Examples of suitable alkenyl radicals include ethenyl, propenyl,2-methylpropenyl, 1,4-butadienyl and the like. Unless otherwisespecified, the term “alkenyl” may include “alkenylene” groups.

The term “alkoxy,” as used herein, alone or in combination, refers to analkyl ether radical, wherein the term alkyl is as defined below.Examples of suitable alkyl ether radicals include methoxy, ethoxy,n-propoxy, isopropoxy, n-butoxy, iso-butoxy, sec-butoxy, tert-butoxy,and the like.

The term “alkyl,” as used herein, alone or in combination, refers to astraight-chain or branched-chain alkyl radical containing from 1 to 20carbon atoms. In certain embodiments, said alkyl will comprise from 1 to10 carbon atoms. In further embodiments, said alkyl will comprise from 1to 6 carbon atoms. Alkyl groups may be optionally substituted as definedherein. Examples of alkyl radicals include methyl, ethyl, n-propyl,isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, pentyl, iso-amyl,hexyl, octyl, noyl and the like. The term “alkylene,” as used herein,alone or in combination, refers to a saturated aliphatic group derivedfrom a straight or branched chain saturated hydrocarbon attached at twoor more positions, such as methylene (—CH₂—). Unless otherwisespecified, the term “alkyl” may include “alkylene” groups.

The term “alkylamino,” as used herein, alone or in combination, refersto an alkyl group attached to the parent molecular moiety through anamino group. Suitable alkylamino groups may be mono- or dialkylated,forming groups such as, for example, N-methylamino, N-ethylamino,N,N-dimethylamino, N,N-ethylmethylamino and the like.

The term “alkylidene,” as used herein, alone or in combination, refersto an alkenyl group in which one carbon atom of the carbon-carbon doublebond belongs to the moiety to which the alkenyl group is attached.

The term “alkylthio,” as used herein, alone or in combination, refers toan alkyl thioether (R—S—) radical wherein the term alkyl is as definedabove and wherein the sulfur may be singly or doubly oxidized. Examplesof suitable alkyl thioether radicals include methylthio, ethylthio,n-propylthio, isopropylthio, n-butylthio, iso-butylthio, sec-butylthio,tert-butylthio, methanesulfonyl, ethanesulfinyl, and the like.

The term “alkynyl,” as used herein, alone or in combination, refers to astraight-chain or branched chain hydrocarbon radical having one or moretriple bonds and containing from 2 to 20 carbon atoms. In certainembodiments, said alkynyl comprises from 2 to 6 carbon atoms. In furtherembodiments, said alkynyl comprises from 2 to 4 carbon atoms. The term“alkynylene” refers to a carbon-carbon triple bond attached at twopositions such as ethynylene (—C:C—, —C≡C—). Examples of alkynylradicals include ethynyl, propynyl, hydroxypropynyl, butyn-1-yl,butyn-2-yl, pentyn-1-yl, 3-methylbutyn-1-yl, hexyn-2-yl, and the like.Unless otherwise specified, the term “alkynyl” may include “alkynylene”groups.

The terms “amido” and “carbamoyl,” as used herein, alone or incombination, refer to an amino group as described below attached to theparent molecular moiety through a carbonyl group, or vice versa. Theterm “C-amido” as used herein, alone or in combination, refers to a—C(═O)—NR₂ group with R as defined herein. The term “N-amido” as usedherein, alone or in combination, refers to a RC(═O)NH— group, with R asdefined herein. The term “acylamino” as used herein, alone or incombination, embraces an acyl group attached to the parent moietythrough an amino group. An example of an “acylamino” group isacetylamino (CH₃C(O)NH—).

The term “amino,” as used herein, alone or in combination, refers to—NRR′, wherein R and R′ are independently chosen from hydrogen, alkyl,acyl, heteroalkyl, aryl, cycloalkyl, heteroaryl, and heterocycloalkyl,any of which may themselves be optionally substituted. Additionally, Rand R′ may combine to form heterocycloalkyl, either of which may beoptionally substituted.

The term “aryl,” as used herein, alone or in combination, means acarbocyclic aromatic system containing one, two or three rings whereinsuch polycyclic ring systems are fused together. The term “aryl”embraces aromatic groups such as phenyl, naphthyl, anthracenyl, andphenanthryl.

The term “arylalkenyl” or “aralkenyl,” as used herein, alone or incombination, refers to an aryl group attached to the parent molecularmoiety through an alkenyl group.

The term “arylalkoxy” or “aralkoxy,” as used herein, alone or incombination, refers to an aryl group attached to the parent molecularmoiety through an alkoxy group.

The term “arylalkyl” or “aralkyl,” as used herein, alone or incombination, refers to an aryl group attached to the parent molecularmoiety through an alkyl group.

The term “arylalkynyl” or “aralkynyl,” as used herein, alone or incombination, refers to an aryl group attached to the parent molecularmoiety through an alkynyl group.

The term “arylalkanoyl” or “aralkanoyl” or “aroyl,” as used herein,alone or in combination, refers to an acyl radical derived from anaryl-substituted alkanecarboxylic acid such as benzoyl, napthoyl,phenylacetyl, 3-phenylpropionyl (hydrocinnamoyl), 4-phenylbutyryl,(2-naphthyl)acetyl, 4-chlorohydrocinnamoyl, and the like.

The term aryloxy as used herein, alone or in combination, refers to anaryl group attached to the parent molecular moiety through an oxy.

The terms “benzo” and “benz,” as used herein, alone or in combination,refer to the divalent radical C₆H₄=derived from benzene. Examplesinclude benzothiophene and benzimidazole.

The term “carbamate,” as used herein, alone or in combination, refers toan ester of carbamic acid (—NHCOO—) which may be attached to the parentmolecular moiety from either the nitrogen or acid end, and which may beoptionally substituted as defined herein.

The term “O-carbamyl” as used herein, alone or in combination, refers toa —OC(O)NRR′, group—with R and R′ as defined herein.

The term “N-carbamyl” as used herein, alone or in combination, refers toa ROC(O)NR′— group, with R and R′ as defined herein.

The term “carbonyl,” as used herein, when alone includes formyl [—C(O)H]and in combination is a —C(O)— group.

The term “carboxyl” or “carboxy,” as used herein, refers to —C(O)OH orthe corresponding “carboxylate” anion, such as is in a carboxylic acidsalt. An “O-carboxy” group refers to a RC(O)O— group, where R is asdefined herein. A “C-carboxy” group refers to a —C(O)OR groups where Ris as defined herein.

The term “cyano,” as used herein, alone or in combination, refers to—CN.

The term “cycloalkyl,” or, alternatively, “carbocycle,” as used herein,alone or in combination, refers to a saturated or partially saturatedmonocyclic, bicyclic or tricyclic alkyl group wherein each cyclic moietycontains from 3 to 12 carbon atom ring members and which may optionallybe a benzo fused ring system which is optionally substituted as definedherein. In certain embodiments, said cycloalkyl will comprise from 3 to7 carbon atoms. Examples of such cycloalkyl groups include cyclopropyl,cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, tetrahydronapthyl,indanyl, octahydronaphthyl, 2,3-dihydro-1H-indenyl, adamantyl and thelike. “Bicyclic” and “tricyclic” as used herein are intended to includeboth fused ring systems, such as decahydronaphthalene,octahydronaphthalene as well as the multicyclic (multicentered)saturated or partially unsaturated type. The latter type of isomer isexemplified in general by, bicyclo[1,1,1]pentane, camphor, adamantane,and bicyclo[3,2,1]octane.

The term “ester,” as used herein, alone or in combination, refers to acarboxy group bridging two moieties linked at carbon atoms.

The term “ether,” as used herein, alone or in combination, refers to anoxy group bridging two moieties linked at carbon atoms.

The term “halo,” or “halogen,” as used herein, alone or in combination,refers to fluorine, chlorine, bromine, or iodine.

The term “haloalkoxy,” as used herein, alone or in combination, refersto a haloalkyl group attached to the parent molecular moiety through anoxygen atom.

The term “haloalkyl,” as used herein, alone or in combination, refers toan alkyl radical having the meaning as defined above wherein one or morehydrogens are replaced with a halogen. Specifically embraced aremonohaloalkyl, dihaloalkyl and polyhaloalkyl radicals. A monohaloalkylradical, for one example, may have an iodo, bromo, chloro or fluoro atomwithin the radical. Dihalo and polyhaloalkyl radicals may have two ormore of the same halo atoms or a combination of different halo radicals.Examples of haloalkyl radicals include fluoromethyl, difluoromethyl,trifluoromethyl, chloromethyl, dichloromethyl, trichloromethyl,pentafluoroethyl, heptafluoropropyl, difluorochloromethyl,dichlorofluoromethyl, difluoroethyl, difluoropropyl, dichloroethyl anddichloropropyl. “Haloalkylene” refers to a haloalkyl group attached attwo or more positions. Examples include fluoromethylene

(—CFH—), difluoromethylene (—CF₂—), chloromethylene (—CHCl—) and thelike.

The term “heteroalkyl,” as used herein, alone or in combination, refersto a stable straight or branched chain hydrocarbon radical, orcombinations thereof, fully saturated or containing from 1 to 3 degreesof unsaturation, consisting of the stated number of carbon atoms andfrom one to three heteroatoms chosen from O, N, and S, and wherein thenitrogen and sulfur atoms may optionally be oxidized and the nitrogenheteroatom may optionally be substituted or quaternized. Theheteroatom(s) O, N and S may be placed at any interior position of theheteroalkyl group. Up to two heteroatoms may be consecutive, such as,for example, —CH₂—NH—OCH₃.

The term “heteroaryl,” as used herein, alone or in combination, refersto a 3 to 7 membered unsaturated heteromonocyclic ring, or a fusedmonocyclic, bicyclic, or tricyclic ring system in which at least one ofthe fused rings is aromatic, which contains at least one atom chosenfrom O, S, and N. In certain embodiments, said heteroaryl will comprisefrom 5 to 7 carbon atoms. The term also embraces fused polycyclic groupswherein heterocyclic rings are fused with aryl rings, wherein heteroarylrings are fused with other heteroaryl rings, wherein heteroaryl ringsare fused with heterocycloalkyl rings, or wherein heteroaryl rings arefused with cycloalkyl rings. Examples of heteroaryl groups includepyrrolyl, pyrrolinyl, imidazolyl, pyrazolyl, pyridyl, pyrimidinyl,pyrazinyl, pyridazinyl, triazolyl, pyranyl, furyl, thienyl, oxazolyl,isoxazolyl, oxadiazolyl, thiazolyl, thiadiazolyl, isothiazolyl, indolyl,isoindolyl, indolizinyl, benzimidazolyl, quinolyl, isoquinolyl,quinoxalinyl, quinazolinyl, indazolyl, benzotriazolyl, benzodioxolyl,benzopyranyl, benzoxazolyl, benzoxadiazolyl, benzothiazolyl,benzothiadiazolyl, benzofuryl, benzothienyl, chromonyl, coumarinyl,benzopyranyl, tetrahydroquinolinyl, tetrazolopyridazinyl,tetrahydroisoquinolinyl, thienopyridinyl, furopyridinyl,pyrrolopyridinyl and the like. Exemplary tricyclic heterocyclic groupsinclude carbazolyl, benzidolyl, phenanthrolinyl, dibenzofuranyl,acridinyl, phenanthridinyl, xanthenyl and the like.

The terms “heterocycloalkyl” and, interchangeably, “heterocycle,” asused herein, alone or in combination, each refer to a saturated,partially unsaturated, or fully unsaturated monocyclic, bicyclic, ortricyclic heterocyclic group containing at least one heteroatom as aring member, wherein each said heteroatom may be independently chosenfrom nitrogen, oxygen, and sulfur. In certain embodiments, saidhetercycloalkyl will comprise from 1 to 4 heteroatoms as ring members.In further embodiments, said hetercycloalkyl will comprise from 1 to 2heteroatoms as ring members. In certain embodiments, saidhetercycloalkyl will comprise from 3 to 8 ring members in each ring. Infurther embodiments, said hetercycloalkyl will comprise from 3 to 7 ringmembers in each ring. In yet further embodiments, said hetercycloalkylwill comprise from 5 to 6 ring members in each ring.

“Heterocycloalkyl” and “heterocycle” are intended to include sulfones,sulfoxides, N-oxides of tertiary nitrogen ring members, and carbocyclicfused and benzo fused ring systems; additionally, both terms alsoinclude systems where a heterocycle ring is fused to an aryl group, asdefined herein, or an additional heterocycle group. Examples ofheterocycle groups include aziridinyl, azetidinyl, 1,3-benzodioxolyl,dihydroisoindolyl, dihydroisoquinolinyl, dihydrocinnolinyl,dihydrobenzodioxinyl, dihydro[1,3]oxazolo[4,5-b]pyridinyl,benzothiazolyl, dihydroindolyl, dihy-dropyridinyl, 1,3-dioxanyl,1,4-dioxanyl, 1,3-dioxolanyl, isoindolinyl, morpholinyl, piperazinyl,pyrrolidinyl, tetrahydropyridinyl, piperidinyl, thiomorpholinyl,3,4-methylenedioxyphenyl and the like. The heterocycle groups may beoptionally substituted unless specifically prohibited.

The term “hydrazinyl” as used herein, alone or in combination, refers totwo amino groups joined by a single bond, i.e., —N—N— and not embodiedin a ring.

The term “hydroxy,” as used herein, alone or in combination, refers to—OH.

The term “hydroxyalkyl,” as used herein, alone or in combination, refersto a hydroxy group attached to the parent molecular moiety through analkyl group.

The term “imino,” as used herein, alone or in combination, refers to═N—.

The term “iminohydroxy,” as used herein, alone or in combination, refersto ═N(OH) and ═N—O—.

The phrase “in the main chain” refers to the longest contiguous oradjacent chain of carbon atoms starting at the point of attachment of agroup to the compounds of any one of the formulas disclosed herein.

The term “isocyanato” refers to a —NCO group.

The term “isothiocyanato” refers to a —NCS group.

The phrase “linear chain of atoms” refers to the longest straight chainof atoms independently selected from carbon, nitrogen, oxygen andsulfur.

The term “lower,” as used herein, alone or in a combination, where nototherwise specifically defined, means containing from 1 to and including6 carbon atoms.

The term “lower aryl,” as used herein, alone or in combination, meansphenyl or naphthyl, which may be optionally substituted as provided.

The term “lower heteroaryl,” as used herein, alone or in combination,means either 1) monocyclic heteroaryl comprising five or six ringmembers, of which between one and four said members may be heteroatomschosen from O, S, and N, or 2) bicyclic heteroaryl, wherein each of thefused rings comprises five or six ring members, comprising between themone to four heteroatoms chosen from O, S, and N.

The term “lower cycloalkyl,” as used herein, alone or in combination,means a monocyclic cycloalkyl having between three and six ring members.Lower cycloalkyls may be unsaturated. Examples of lower cycloalkylinclude cyclopropyl, cyclobutyl, cyclopentyl, and cyclohexyl.

The term “lower heterocycloalkyl,” as used herein, alone or incombination, means a monocyclic heterocycloalkyl having between threeand six ring members, of which between one and four may be heteroatomschosen from O, S, and N. Examples of lower heterocycloalkyls includepyrrolidinyl, imidazolidinyl, pyrazolidinyl, piperidinyl, piperazinyl,and morpholinyl. Lower heterocycloalkyls may be unsaturated.

The term “lower amino,” as used herein, alone or in combination, refersto —NRR′, wherein R and R′ are independently chosen from hydrogen, loweralkyl, and lower heteroalkyl, any of which may be optionallysubstituted. Additionally, the R and R′ of a lower amino group maycombine to form a five- or six-membered heterocycloalkyl, either ofwhich may be optionally substituted.

The term “mercaptyl” as used herein, alone or in combination, refers toan RS— group, where R is as defined herein.

The term “nitro,” as used herein, alone or in combination, refers to—NO₂.

The terms “oxy” or “oxa,” as used herein, alone or in combination, referto —O—.

The term “oxo,” as used herein, alone or in combination, refers to ═O.

The term “perhaloalkoxy” refers to an alkoxy group where all of thehydrogen atoms are replaced by halogen atoms.

The term “perhaloalkyl” as used herein, alone or in combination, refersto an alkyl group where all of the hydrogen atoms are replaced byhalogen atoms.

The terms “sulfonate,” “sulfonic acid,” and “sulfonic,” as used herein,alone or in combination, refer the —SO₃H group and its anion as thesulfonic acid is used in salt formation.

The term “sulfanyl,” as used herein, alone or in combination, refers to—S—.

The term “sulfinyl,” as used herein, alone or in combination, refers to—S(O)—.

The term “sulfonyl,” as used herein, alone or in combination, refers to—S(O)₂—.

The term “N-sulfonamido” refers to a RS(═O)₂NR′— group with R and R′ asdefined herein.

The term “S-sulfonamido” refers to a —S(═O)₂NRR′, group, with R and R′as defined herein.

The terms “thia” and “thio,” as used herein, alone or in combination,refer to a —S— group or an ether wherein the oxygen is replaced withsulfur. The oxidized derivatives of the thio group, namely sulfinyl andsulfonyl, are included in the definition of thia and thio.

The term “thiol,” as used herein, alone or in combination, refers to an—SH group.

The term “thiocarbonyl,” as used herein, when alone includes thioformyl—C(S)H and in combination is a —C(S)— group.

The term “N-thiocarbamyl” refers to an ROC(S)NR′— group, with R and R′as defined herein.

The term “O-thiocarbamyl” refers to a —OC(S)NRR′, group with R and R′ asdefined herein.

The term “thiocyanato” refers to a —CNS group.

The term “trihalomethoxy” refers to a X₃CO— group where X is a halogen.

Any definition herein may be used in combination with any otherdefinition to describe a composite structural group. By convention, thetrailing element of any such definition is that which attaches to theparent moiety. For example, the composite group alkylamido wouldrepresent an alkyl group attached to the parent molecule through anamido group, and the term alkoxyalkyl would represent an alkoxy groupattached to the parent molecule through an alkyl group.

When a group is defined to be “null,” what is meant is that said groupis absent.

The term “optionally substituted” means the anteceding group may besubstituted or unsubstituted. When substituted, the substituents of an“optionally substituted” group may include, without limitation, one ormore substituents independently selected from the following groups or aparticular designated set of groups, alone or in combination: loweralkyl, lower alkenyl, lower alkynyl, lower alkanoyl, lower heteroalkyl,lower heterocycloalkyl, lower haloalkyl, lower haloalkenyl, lowerhaloalkynyl, lower perhaloalkyl, lower perhaloalkoxy, lower cycloalkyl,phenyl, aryl, aralkyl, aryloxy, lower alkoxy, lower haloalkoxy, oxo,lower acyloxy, carbonyl, carboxyl, lower alkylcarbonyl, lowercarboxyester, lower carboxamido, cyano, hydrogen, halogen, hydroxy,amino, lower alkylamino, arylamino, amido, nitro, thiol, loweralkylthio, lower haloalkylthio, lower perhaloalkylthio, arylthio,sulfonate, sulfonic acid, trisubstituted silyl, N₃, SH, SCH₃, C(O)CH₃,CO₂CH₃, CO₂H, pyridinyl, thiophene, furanyl, lower carbamate, and lowerurea. Two substituents may be joined together to form a fused five-,six-, or seven-membered carbocyclic or heterocyclic ring consisting ofzero to three heteroatoms, for example forming methylenedioxy orethylenedioxy. An optionally substituted group may be unsubstituted(e.g., —CH₂CH₃), fully substituted (e.g., —CF₂CF₃), monosubstituted(e.g., —CH₂CH₂F) or substituted at a level anywhere in-between fullysubstituted and monosubstituted (e.g., —CH₂CF₃). Where substituents arerecited without qualification as to substitution, both substituted andunsubstituted forms are encompassed. Where a substituent is qualified as“substituted,” the substituted form is specifically intended.Additionally, different sets of optional substituents to a particularmoiety may be defined as needed; in these cases, the optionalsubstitution will be as defined, often immediately following the phrase,“optionally substituted with.”

The term R or the term R′, appearing by itself and without a numberdesignation, unless otherwise defined, refers to a moiety chosen fromhydrogen, alkyl, cycloalkyl, heteroalkyl, aryl, heteroaryl andheterocycloalkyl, any of which may be optionally substituted. Such R andR′ groups should be understood to be optionally substituted as definedherein. Whether an R group has a number designation or not, every Rgroup, including R, R′ and R^(n) where n=(1, 2, 3, . . . n), everysubstituent, and every term should be understood to be independent ofevery other in terms of selection from a group. Should any variable,substituent, or term (e.g. aryl, heterocycle, R, etc.) occur more thanone time in a formula or generic structure, its definition at eachoccurrence is independent of the definition at every other occurrence.Those of skill in the art will further recognize that certain groups maybe attached to a parent molecule or may occupy a position in a chain ofelements from either end as written. Thus, by way of example only, anunsymmetrical group such as —C(O)N(R)— may be attached to the parentmoiety at either the carbon or the nitrogen.

Asymmetric centers exist in the compounds disclosed herein. Thesecenters are designated by the symbols “R” or “S,” depending on theconfiguration of substituents around the chiral carbon atom. It shouldbe understood that the invention encompasses all stereochemical isomericforms, including diastereomeric, enantiomeric, and epimeric forms, aswell as d-isomers and 1-isomers, and mixtures thereof. Individualstereoisomers of compounds can be prepared synthetically fromcommercially available starting materials which contain chiral centersor by preparation of mixtures of enantiomeric products followed byseparation such as conversion to a mixture of diastereomers followed byseparation or recrystallization, chromatographic techniques, directseparation of enantiomers on chiral chromatographic columns, or anyother appropriate method known in the art. Starting compounds ofparticular stereochemistry are either commercially available or can bemade and resolved by techniques known in the art. Additionally, thecompounds disclosed herein may exist as geometric isomers. The presentinvention includes all cis, trans, syn, anti, entgegen (E), and zusammen(Z) isomers as well as the appropriate mixtures thereof. Additionally,compounds may exist as tautomers; all tautomeric isomers are provided bythis invention. Additionally, the compounds disclosed herein can existin unsolvated as well as solvated forms with pharmaceutically acceptablesolvents such as water, ethanol, and the like. In general, the solvatedforms are considered equivalent to the unsolvated forms.

The term “bond” refers to a covalent linkage between two atoms, or twomoieties when the atoms joined by the bond are considered to be part oflarger substructure.

A bond may be single, double, or triple unless otherwise specified. Adashed line between two atoms in a drawing of a molecule indicates thatan additional bond may be present or absent at that position.

The term “disease” as used herein is intended to be generallysynonymous, and is used interchangeably with, the terms “disorder” and“condition” (as in medical condition), in that all reflect an abnormalcondition of the human or animal body or of one of its parts thatimpairs normal functioning, is typically manifested by distinguishingsigns and symptoms, and causes the human or animal to have a reducedduration or quality of life.

The term “combination therapy” means the administration of two or moretherapeutic agents to treat a therapeutic condition or disorderdescribed in the present disclosure. Such administration encompassesco-administration of these therapeutic agents in a substantiallysimultaneous manner, such as in a single capsule having a fixed ratio ofactive ingredients or in multiple, separate capsules for each activeingredient. In addition, such administration also encompasses use ofeach type of therapeutic agent in a sequential manner. In either case,the treatment regimen will provide beneficial effects of the drugcombination in treating the conditions or disorders described herein.

“PASK inhibitor” as used herein refers to a compound that exhibits an(IC₅₀/EC₅₀) with respect to PASK activity of no more than about 100 μMand more typically not more than about 50 μM, as measured in the PASKassay described generally hereinbelow. IC₅₀ is that concentration ofinhibitors which reduces the activity of PASK to half-maximal level.Certain compounds disclosed herein have been discovered to exhibitinhibition against PASK.

The phrase “therapeutically effective” is intended to qualify the amountof active ingredients used in the treatment of a disease or disorder.This amount will achieve the goal of reducing or eliminating the saiddisease or disorder.

The term “therapeutically acceptable” refers to those compounds (orsalts, prodrugs, tautomers, zwitterionic forms, etc.) which are suitablefor use in contact with the tissues of patients without undue toxicity,irritation, and allergic response, are commensurate with a reasonablebenefit/risk ratio, and are effective for their intended use.

As used herein, reference to “treatment” of a patient is intended toinclude prophylaxis. The term “patient” means all mammals includinghumans. Examples of patients include humans, cows, dogs, cats, goats,sheep, pigs, and rabbits. Preferably, the patient is a human.

The term “prodrug” refers to a compound that is made more active invivo. Certain compounds disclosed herein may also exist as prodrugs, asdescribed in Hydrolysis in Drug and Prodrug Metabolism: Chemistry,Biochemistry, and Enzymology (Testa, Bernard and Mayer, Joachim M.Wiley-VHCA, Zurich, Switzerland 2003). Prodrugs of the compoundsdescribed herein are structurally modified forms of the compound thatreadily undergo chemical changes under physiological conditions toprovide the compound. Additionally, prodrugs can be converted to thecompound by chemical or biochemical methods in an ex vivo environment.For example, prodrugs can be slowly converted to a compound when placedin a transdermal patch reservoir with a suitable enzyme or chemicalreagent. Prodrugs are often useful because, in some situations, they maybe easier to administer than the compound, or parent drug. They may, forinstance, be bioavailable by oral administration whereas the parent drugis not. The prodrug may also have improved solubility in pharmaceuticalcompositions over the parent drug. A wide variety of prodrug derivativesare known in the art, such as those that rely on hydrolytic cleavage oroxidative activation of the prodrug. An example, without limitation, ofa prodrug would be a compound which is administered as an ester (the“prodrug”), but then is metabolically hydrolyzed to the carboxylic acid,the active entity. Additional examples include peptidyl derivatives of acompound.

The compounds disclosed herein can exist as therapeutically acceptablesalts. The present invention includes compounds listed above in the formof salts, including acid addition salts. Suitable salts include thoseformed with both organic and inorganic acids. Such acid addition saltswill normally be pharmaceutically acceptable. However, salts ofnon-pharmaceutically acceptable salts may be of utility in thepreparation and purification of the compound in question. Basic additionsalts may also be formed and be pharmaceutically acceptable. For a morecomplete discussion of the preparation and selection of salts, refer toPharmaceutical Salts: Properties, Selection, and Use (Stahl, P.Heinrich. Wiley-VCHA, Zurich, Switzerland, 2002).

The term “therapeutically acceptable salt,” as used herein, representssalts or zwitterionic forms of the compounds disclosed herein which arewater or oil-soluble or dispersible and therapeutically acceptable asdefined herein. The salts can be prepared during the final isolation andpurification of the compounds or separately by reacting the appropriatecompound in the form of the free base with a suitable acid.

While it may be possible for the compounds of the subject invention tobe administered as the raw chemical, it is also possible to present themas a pharmaceutical formulation. Accordingly, provided herein arepharmaceutical formulations which comprise one or more of certaincompounds disclosed herein, or one or more pharmaceutically acceptablesalts, esters, prodrugs, amides, or solvates thereof, together with oneor more pharmaceutically acceptable carriers thereof and optionally oneor more other therapeutic ingredients. The carrier(s) must be“acceptable” in the sense of being compatible with the other ingredientsof the formulation and not deleterious to the recipient thereof. Properformulation is dependent upon the route of administration chosen. Any ofthe well-known techniques, carriers, and excipients may be used assuitable and as understood in the art; e.g., in Remington'sPharmaceutical Sciences. The pharmaceutical compositions disclosedherein may be manufactured in any manner known in the art, e.g., bymeans of conventional mixing, dissolving, granulating, dragee-making,levigating, emulsifying, encapsulating, entrapping or compressionprocesses.

The formulations include those suitable for oral, parenteral (includingsubcutaneous, intradermal, intramuscular, intravenous, intraarticular,and intramedullary), intraperitoneal, transmucosal, transdermal, rectaland topical (including dermal, buccal, sublingual and intraocular)administration although the most suitable route may depend upon forexample the condition and disorder of the recipient. The formulationsmay conveniently be presented in unit dosage form and may be prepared byany of the methods well known in the art of pharmacy.

Typically, these methods include the step of bringing into association acompound of the subject invention or a pharmaceutically acceptable salt,ester, amide, prodrug or solvate thereof (“active ingredient”) with thecarrier which constitutes one or more accessory ingredients. In general,the formulations are prepared by uniformly and intimately bringing intoassociation the active ingredient with liquid carriers or finely dividedsolid carriers or both and then, if necessary, shaping the product intothe desired formulation.

Formulations of the compounds disclosed herein suitable for oraladministration may be presented as discrete units such as capsules,cachets or tablets each containing a predetermined amount of the activeingredient; as a powder or granules; as a solution or a suspension in anaqueous liquid or a non-aqueous liquid; or as an oil-in-water liquidemulsion or a water-in-oil liquid emulsion. The active ingredient mayalso be presented as a bolus, electuary or paste.

Pharmaceutical preparations which can be used orally include tablets,push-fit capsules made of gelatin, as well as soft, sealed capsules madeof gelatin and a plasticizer, such as glycerol or sorbitol. Tablets maybe made by compression or molding, optionally with one or more accessoryingredients. Compressed tablets may be prepared by compressing in asuitable machine the active ingredient in a free-flowing form such as apowder or granules, optionally mixed with binders, inert diluents, orlubricating, surface active or dispersing agents. Molded tablets may bemade by molding in a suitable machine a mixture of the powdered compoundmoistened with an inert liquid diluent. The tablets may optionally becoated or scored and may be formulated so as to provide slow orcontrolled release of the active ingredient therein. All formulationsfor oral administration should be in dosages suitable for suchadministration. The push-fit capsules can contain the active ingredientsin admixture with filler such as lactose, binders such as starches,and/or lubricants such as talc or magnesium stearate and, optionally,stabilizers. In soft capsules, the active compounds may be dissolved orsuspended in suitable liquids, such as fatty oils, liquid paraffin, orliquid polyethylene glycols. In addition, stabilizers may be added.Dragee cores are provided with suitable coatings. For this purpose,concentrated sugar solutions may be used, which may optionally containgum arabic, talc, polyvinyl pyrrolidone, carbopol gel, polyethyleneglycol, and/or titanium dioxide, lacquer solutions, and suitable organicsolvents or solvent mixtures. Dyestuffs or pigments may be added to thetablets or dragee coatings for identification or to characterizedifferent combinations of active compound doses.

The compounds may be formulated for parenteral administration byinjection, e.g., by bolus injection or continuous infusion. Formulationsfor injection may be presented in unit dosage form, e.g., in ampoules orin multi-dose containers, with an added preservative. The compositionsmay take such forms as suspensions, solutions or emulsions in oily oraqueous vehicles, and may contain formulatory agents such as suspending,stabilizing and/or dispersing agents. The formulations may be presentedin unit-dose or multi-dose containers, for example sealed ampoules andvials, and may be stored in powder form or in a freeze-dried(lyophilized) condition requiring only the addition of the sterileliquid carrier, for example, saline or sterile pyrogen-free water,immediately prior to use.

Extemporaneous injection solutions and suspensions may be prepared fromsterile powders, granules and tablets of the kind previously described.

Formulations for parenteral administration include aqueous andnon-aqueous (oily) sterile injection solutions of the active compoundswhich may contain antioxidants, buffers, bacteriostats and solutes whichrender the formulation isotonic with the blood of the intendedrecipient; and aqueous and non-aqueous sterile suspensions which mayinclude suspending agents and thickening agents. Suitable lipophilicsolvents or vehicles include fatty oils such as sesame oil, or syntheticfatty acid esters, such as ethyl oleate or triglycerides, or liposomes.Aqueous injection suspensions may contain substances which increase theviscosity of the suspension, such as sodium carboxymethyl cellulose,sorbitol, or dextran. Optionally, the suspension may also containsuitable stabilizers or agents which increase the solubility of thecompounds to allow for the preparation of highly concentrated solutions.

In addition to the formulations described previously, the compounds mayalso be formulated as a depot preparation. Such long acting formulationsmay be administered by implantation (for example subcutaneously orintramuscularly) or by intramuscular injection. Thus, for example, thecompounds may be formulated with suitable polymeric or hydrophobicmaterials (for example as an emulsion in an acceptable oil) or ionexchange resins, or as sparingly soluble derivatives, for example, as asparingly soluble salt.

For buccal or sublingual administration, the compositions may take theform of tablets, lozenges, pastilles, or gels formulated in conventionalmanner. Such compositions may comprise the active ingredient in aflavored basis such as sucrose and acacia or tragacanth.

The compounds may also be formulated in rectal compositions such assuppositories or retention enemas, e.g., containing conventionalsuppository bases such as cocoa butter, polyethylene glycol, or otherglycerides.

Certain compounds disclosed herein may be administered topically, thatis by non-systemic administration. This includes the application of acompound disclosed herein externally to the epidermis or the buccalcavity and the instillation of such a compound into the ear, eye andnose, such that the compound does not significantly enter the bloodstream. In contrast, systemic administration refers to oral,intravenous, intraperitoneal and intramuscular administration.

Formulations suitable for topical administration include liquid orsemi-liquid preparations suitable for penetration through the skin tothe site of inflammation such as gels, liniments, lotions, creams,ointments or pastes, and drops suitable for administration to the eye,ear or nose. The active ingredient for topical administration maycomprise, for example, from 0.001% to 10% w/w (by weight) of theformulation. In certain embodiments, the active ingredient may compriseas much as 10% w/w. In other embodiments, it may comprise less than 5%w/w. In certain embodiments, the active ingredient may comprise from 2%w/w to 5% w/w. In other embodiments, it may comprise from 0.1% to 1% w/wof the formulation. For administration by inhalation, compounds may beconveniently delivered from an insufflator, nebulizer pressurized packsor other convenient means of delivering an aerosol spray. Pressurizedpacks may comprise a suitable propellant such asdichlorodifluoromethane, trichlorofluoromethane,dichlorotetrafluoroethane, carbon dioxide or other suitable gas. In thecase of a pressurized aerosol, the dosage unit may be determined byproviding a valve to deliver a metered amount.

Alternatively, for administration by inhalation or insufflation, thecompounds according to the invention may take the form of a dry powdercomposition, for example a powder mix of the compound and a suitablepowder base such as lactose or starch. The powder composition may bepresented in unit dosage form, in for example, capsules, cartridges,gelatin or blister packs from which the powder may be administered withthe aid of an inhalator or insufflator.

Preferred unit dosage formulations are those containing an effectivedose, as herein below recited, or an appropriate fraction thereof, ofthe active ingredient.

It should be understood that in addition to the ingredients particularlymentioned above, the formulations described above may include otheragents conventional in the art having regard to the type of formulationin question, for example those suitable for oral administration mayinclude flavoring agents.

Compounds may be administered orally or via injection at a dose of from0.1 to 500 mg/kg per day. The dose range for adult humans is generallyfrom 5 mg to 2 g/day. Tablets or other forms of presentation provided indiscrete units may conveniently contain an amount of one or morecompounds which is effective at such dosage or as a multiple of thesame, for instance, units containing 5 mg to 500 mg, usually around 10mg to 200 mg.

The amount of active ingredient that may be combined with the carriermaterials to produce a single dosage form will vary depending upon thehost treated and the particular mode of administration.

The compounds can be administered in various modes, e.g. orally,topically, or by injection. The precise amount of compound administeredto a patient will be the responsibility of the attendant physician. Thespecific dose level for any particular patient will depend upon avariety of factors including the activity of the specific compoundemployed, the age, body weight, general health, sex, diets, time ofadministration, route of administration, rate of excretion, drugcombination, the precise disorder being treated, and the severity of theindication or condition being treated. Also, the route of administrationmay vary depending on the condition and its severity.

In certain instances, it may be appropriate to administer at least oneof the compounds described herein (or a pharmaceutically acceptablesalt, ester, or prodrug thereof) in combination with another therapeuticagent. By way of example only, if one of the side effects experienced bya patient upon receiving one of the compounds herein is hypertension,then it may be appropriate to administer an anti-hypertensive agent incombination with the initial therapeutic agent. Or, by way of exampleonly, the therapeutic effectiveness of one of the compounds describedherein may be enhanced by administration of an adjuvant (i.e., by itselfthe adjuvant may only have minimal therapeutic benefit, but incombination with another therapeutic agent, the overall therapeuticbenefit to the patient is enhanced). Or, by way of example only, thebenefit of experienced by a patient may be increased by administeringone of the compounds described herein with another therapeutic agent(which also includes a therapeutic regimen) that also has therapeuticbenefit. By way of example only, in a treatment for diabetes involvingadministration of one of the compounds described herein, increasedtherapeutic benefit may result by also providing the patient withanother therapeutic agent for diabetes. In any case, regardless of thedisease, disorder or condition being treated, the overall benefitexperienced by the patient may simply be additive of the two therapeuticagents or the patient may experience a synergistic benefit.

Specific, non-limiting examples of possible combination therapiesinclude use of a compound as disclosed herein, and at least one otheragent selected from the group comprising:

-   -   a) anti-diabetic agents such as insulin, insulin derivatives and        mimetics; insulin secretagogues such as the sulfonylureas, e.g.,        Glipizide, glyburide and Amaryl; insulinotropic sulfonylurea        receptor ligands such as meglitinides, e.g., nateglinide and        repaglinide; insulin sensitizer such as protein tyrosine        phosphatase-1B (PTP-1B) inhibitors such as PTP-112; GSK3        (glycogen synthase kinase-3) inhibitors such as SB-517955,        SB-4195052, SB-216763, NN-57-05441 and NN-57-05445; RXR ligands        such as GW-0791 and AGN-194204; sodium-dependent glucose        co-transporter inhibitors such as T-1095; glycogen phosphorylase        A inhibitors such as BAY R3401; biguanides such as metformin;        alpha-glucosidase inhibitors such as acarbose; GLP-1 (glucagon        like peptide-1), GLP-1 analogs such as Exendin-4 and GLP-1        mimetics; DPPIV (dipeptidyl peptidase IV) inhibitors such as        DPP728, LAF237 (vildagliptin—Example 1 of WO 00/34241), MK-0431,        saxagliptin, GSK23A; an AGE breaker; a thiazolidinedione        derivative (glitazone) such as pioglitazone or rosiglitazone;        and a non-glitazone type PPARδ agonist e.g. GI-262570;    -   b) hypolipidemic agents such as 3-hydroxy-3-methyl-glutaryl        coenzyme A (HMG-CoA) reductase inhibitors, e.g., lovastatin,        pitavastatin, simvastatin, pravastatin, cerivastatin,        mevastatin, velostatin, fluvastatin, dalvastatin, atorvastatin,        rosuvastatin and rivastatin; squalene synthase inhibitors; FXR        (farnesoid X receptor) and LXR (liver X receptor) ligands;        cholestyramine; fibrates; nicotinic acid and aspirin;    -   c) an anti-obesity agent or appetite regulating agent such as        phentermine, leptin, bromocriptine, dexamphetamine, amphetamine,        fenfluramine, dexfenfluramine, sibutramine, orlistat,        dexfenfluramine, mazindol, phentermine, phendimetrazine,        diethylpropion, fluoxetine, bupropion, topiramate,        diethylpropion, benzphetamine, phenylpropanolamine or ecopipam,        ephedrine, pseudoephedrine or cannabinoid receptor antagonists;    -   d) anti-hypertensive agents, e.g., loop diuretics such as        ethacrynic acid, furosemide and torsemide; diuretics such as        thiazide derivatives, chlorothiazide, hydrochlorothiazide,        amiloride; angiotensin converting enzyme (ACE) inhibitors such        as benazepril, captopril, enalapril, fosinopril, lisinopril,        moexipril, perinodopril, quinapril, ramipril and trandolapril;        inhibitors of the Na—K-ATPase membrane pump such as digoxin;        neutral endopeptidase (NEP) inhibitors e.g. thiorphan,        terteo-thiorphan, SQ29072; ECE inhibitors e.g. SLV306; ACE/NEP        inhibitors such as omapatrilat, sampatrilat and fasidotril;        angiotensin n antagonists such as candesartan, eprosartan,        irbesartan, losartan, tehnisartan and valsartan, in particular        valsartan; renin inhibitors such as aliskiren, terlakiren,        ditekiren, RO 66-1132, RO-66-1168; β-adrenergic receptor        blockers such as acebutolol, atenolol, betaxolol, bisoprolol,        metoprolol, nadolol, propranolol, sotalol and timolol; inotropic        agents such as digoxin, dobutamine and milrinone; calcium        channel blockers such as amlodipine, bepridil, diltiazem,        felodipine, nicardipine, nimodipine, nifedipine, nisoldipine and        verapamil; aldosterone receptor antagonists; and aldosterone        synthase inhibitors;    -   e) an HDL increasing compound;    -   f) cholesterol absorption modulator such as etizimibe and        KT6-971;    -   g) Apo-A1 analogues and mimetics;    -   h) thrombin inhibitors such as Ximelagatran;    -   i) aldosterone inhibitors such as anastrazole, fadrazole, and        eplerenone;    -   j) inhibitors of platelet aggregation such as aspirin, and        clopidogrel bisulfate;    -   k) estrogen, testosterone, a selective estrogen receptor        modulator, and a selective androgen receptor modulator;    -   l) a chemotherapeutic agent such as aromatase inhibitors e.g.        femara, anti-estrogens, topoisomerase I inhibitors,        topoisomerase II inhibitors, microtubule active agents,        alkylating agents, antineoplastic antimetabolites, platin        compounds, and compounds decreasing the protein kinase activity        such as a PDGF receptor tyrosine kinase inhibitor such as        miatinib; and    -   m) an agent interacting with a 5-HT3 receptor and/or an agent        interacting with 5-HT4 receptor such as tegaserod described in        the U.S. Pat. No. 5,510,353 as example 13, tegaserod hydrogen        maleate, cisapride, and cilansetron.

In any case, the multiple therapeutic agents (at least one of which is acompound disclosed herein) may be administered in any order or evensimultaneously. If simultaneously, the multiple therapeutic agents maybe provided in a single, unified form, or in multiple forms (by way ofexample only, either as a single pill or as two separate pills). One ofthe therapeutic agents may be given in multiple doses, or both may begiven as multiple doses. If not simultaneous, the timing between themultiple doses may be any duration of time ranging from a few minutes tofour weeks.

Thus, in another aspect, certain embodiments provide methods fortreating PASK-mediated disorders in a human or animal subject in need ofsuch treatment comprising administering to said subject an amount of acompound disclosed herein effective to reduce or prevent said disorderin the subject, optionally in combination with at least one additionalagent that is known in the art. In a related aspect, certain embodimentsprovide therapeutic compositions comprising at least one compounddisclosed herein in combination with one or more additional agents forthe treatment of PASK-mediated disorders.

Recent studies have found that elevated medium glucose concentrationscaused post-translational activation of PASK. It has also beendemonstrated that PASK activity is required for glucose-stimulatedinsulin expression, as shown by studies in PASK1 mice. It has also beendemonstrated that PASK deletion results in nearly complete resistance tothe phenotypes caused by a high-fat diet, including obesity, insulinresistance and hepatic fat accumulation. It appears that PASK inhibitioncan provide an effective therapeutic strategy for the treatment ofdiseases, for example Type 2 diabetes, insulin resistance in general,and the metabolic syndrome.

Metabolic syndrome (also known as metabolic syndrome X) is characterizedby having at least three of the following symptoms: insulin resistance;abdominal fat—in men this is defined as a 40 inch waist or larger, inwomen 35 inches or larger; high blood sugar levels—at least 110milligrams per deciliter (mg/dL) after fasting; high triglycerides—atleast 150 mg/dL in the blood stream; low HDL—less than 40 mg/dL;pro-thrombotic state (e.g. high fibrinogen or plasminogen activatorinhibitor in the blood); or blood pressure of 130/85 mmHg or higher. Aconnection has been found between metabolic syndrome and otherconditions such as obesity, high blood pressure and high levels of LDLcholesterol, all of which are risk factors for cardiovascular diseases.For example, an increased link between metabolic syndrome andatherosclerosis has been shown. People with metabolic syndrome are alsomore prone to developing type 2 diabetes, as well as PCOS (polycysticovarian syndrome) in women and prostate cancer in men.

As described above, insulin resistance can be manifested in severalways, including type 2 diabetes. Type 2 diabetes is the condition mostobviously linked to insulin resistance. Compensatory hyperinsulinemiahelps maintain normal glucose levels-often for decades, before overtdiabetes develops. Eventually the beta cells of the pancreas are unableto overcome insulin resistance through hypersecretion. Glucose levelsrise, and a diagnosis of diabetes can be made. Patients with type 2diabetes remain hyperinsulinemic until they are in an advanced stage ofdisease. As described above, insulin resistance can also correlate withhypertension. One half of patients with essential hypertension areinsulin resistant and hyperinsulinemic, and there is evidence that bloodpressure is linked to the degree of insulin resistance. Hyperlipidemia,too, is associated with insulin resistance. The lipid profile ofpatients with type 2 diabetes includes increased serum very-low-densitylipoprotein cholesterol and triglyceride levels and, sometimes, adecreased low-density lipoprotein cholesterol level. Insulin resistancehas been found in persons with low levels of high-density lipoprotein.Insulin levels have also been linked to very-low-density lipoproteinsynthesis and plasma triglyceride levels.

Accordingly, also disclosed are methods of treating insulin resistancein a subject comprising selecting a subject in need of treatment forinsulin resistance; and administering to the subject an effective amountof a compound that inhibits PASK. Specific diseases to be treated by thecompounds, compositions, and methods disclosed herein are those mediatedat least in part by PASK. Accordingly, disclosed herein are methods: forreducing glycogen accumulation in a subject; for raising HDL or HDLc,lowering LDL or LDLc, shifting LDL particle size from small dense tonormal LDL, lowering VLDL, lowering triglycerides, or inhibitingcholesterol absorption in a subject; for reducing insulin resistance,enhancing glucose utilization or lowering blood pressure in a subject;for reducing visceral fat in a subject; for reducing serum transaminasesin a subject; for reducing hemoglobin A1c in a subject; or for treatingdisease; all comprising the administration of a therapeutic amount of acompound as described herein, to a patient in need thereof. In furtherembodiments, the disease to be treated may be a metabolic disease. Infurther embodiments, the metabolic disease may be chosen from: obesity,diabetes melitus, especially Type 2 diabetes, hyperinsulinemia, glucoseintolerance, metabolic syndrome X, dyslipidemia, hypertriglyceridemia,hypercholesterolemia, and hepatic steatosis. In other embodiments, thedisease to be treated may be chosen from: cardiovascular diseasesincluding vascular disease, atherosclerosis, coronary heart disease,cerebrovascular disease, heart failure and peripheral vessel disease. Inpreferred embodiments, the methods above do not result in the inductionor maintenance of a hypoglycemic state.

In further embodiments, the metabolic disease may be a neurologicaldisease known to be associated with metabolic disease and/or insulinresistance, such as Alzheimer's disease.

Additionally, the PASK modulators disclosed herein may be used to treatproliferative disorders such as cancers. Hematological andnon-hematological cancers which may be treated or prevented include butare not limited to multiple myeloma, acute and chronic leukemiasincluding Acute Lymphocytic Leukemia (ALL), Chronic Lymphocytic Leukemia(CLL), and Chronic Myelogenous Leukemia (CLL), lymphomas, includingHodgkin's lymphoma and non-Hodgkin's lymphoma (low, intermediate, andhigh grade), malignancies of the brain, head and neck, breast, lung,reproductive tract, upper digestive tract, pancreas, liver, renal,bladder, prostate and colon/rectum.

Besides being useful for human treatment, certain compounds andformulations disclosed herein may also be useful for veterinarytreatment of companion animals, exotic animals and farm animals,including mammals, rodents, and the like. More preferred animals includehorses, dogs, and cats.

REFERENCES CITED

The following is a list of references cited herein which, while notnecessarily comprehensive, is provided for the convenience of thereader. All references, patents, and patent applications cited hereinare hereby incorporated by reference as if written herein in theirentireties. When the teachings of these references contradict theteachings presented expressly herein, the present disclosure controls.

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GENERAL SYNTHETIC METHODS FOR PREPARING COMPOUNDS

The following schemes can generally be used to practice the presentinvention.

Step 1 Synthesis of methyl 4-fluoro-3-nitrobenzoate

Thionyl chloride (6.5 g, 54.62 mmol, 1.01 equiv) was added dropwise,with stirring at 0° C., to a methanolic solution (60 mL) of4-fluoro-3-nitrobenzoic acid (10 g, 54.05 mmol, 1.00 equiv) in a 250-mLround-bottom flask, then stirred for 3 hr at reflux in an oil bath. Theresulting mixture was concentrated under vacuum, diluted with 100 mL ofEtOAc, and the pH of the solution adjusted to 7-8 with aqueous NaHCO₃(saturated). The solution was then extracted with 6×50 mL of ethylacetate, the organic layers combined and dried over anhydrous sodiumsulfate, and concentrated under vacuum, affording 12.42 g (crude) ofmethyl 4-fluoro-3-nitrobenzoate as a white solid.

Step 2 Synthesis of methyl4-(2-methoxy-2-oxo-1-phenylethylamino)-3-nitrobenzoate

A solution of methyl 2-amino-2-phenylacetate hydrochloride (2.5 g, 12.38mmol, 1.00 equiv) in DMF (30 mL), methyl 4-fluoro-3-nitrobenzoate (5 g,25.13 mmol, 2.00 equiv), and DIEA (5 g, 38.76 mmol, 3.13 equiv) wasreacted overnight at 30° C. in a 100-mL round-bottom flask. The reactionwas then quenched by the addition of 200 mL of water, and the solidswere collected by filtration. Purification via silica gel column(petroleum ether/EtOAc (50:1)) yielded 3.82 g (90%) of methyl4-(2-methoxy-2-oxo-1-phenylethylamino)-3-nitrobenzoate as a yellowsolid. LC-MS (ES, m/z): 345 [M+H]⁺.

Step 3 Synthesis of methyl3-oxo-2-phenyl-1,2,3,4-tetrahydroquinoxaline-6-carboxylate

Iron (34.89 g, 623.04 mmol, 5.00 equiv) was added portionwise to astirred solution of methyl4-(2-methoxy-2-oxo-1-phenylethylamino)-3-nitrobenzoate (42.87 g, 124.62mmol, 1.00 equiv) and aqueous NH₄Cl (32.1 g, 600.00 mmol, 5.00 equiv, 80mL) in methanol (300 mL). The resulting solution was heated under refluxfor 5 h. Upon cooling, the solids were filtered out. The resultingfiltrate was concentrated under vacuum, affording 19.81 g (56%) ofmethyl 3-oxo-2-phenyl-1,2,3,4-tetrahydroquinoxaline-6-carboxylate as ayellow solid. LC-MS (ES, m/z): 283 [M+H]⁺.

Step 4 Synthesis of methyl3-oxo-2-phenyl-3,4-dihydroquinoxaline-6-carboxylate

DDQ (21.25 g, 93.6 mmol, 2.62 equiv) was added to a stirred solution ofmethyl 3-oxo-2-phenyl-1,2,3,4-tetrahydroquinoxaline-6-carboxylate (10.07g, 35.7 mmol, 1.00 equiv) in dioxane (750 mL) and allowed to react, withstirring, overnight at room temperature. The solids were collected byfiltration. The filter cake was washed with 2×500 mL of aqueous K₂CO₃(saturated). This resulted in 7.29 g (crude) of methyl3-oxo-2-phenyl-3,4-dihydroquinoxaline-6-carboxylate as an off-whitesolid. LC-MS (ES, m/z): 281 [M+H]⁺.

Step 5 Synthesis of methyl 3-bromo-2-phenylquinoxaline-6-carboxylate

A solution of methyl 3-oxo-2-phenyl-3,4-dihydroquinoxaline-6-carboxylate(2.1 g, 7.50 mmol, 1.00 equiv) and POBr₃ (21.5 g, 74.91 mmol, 10.00equiv) in CH₃CN (120 mL) in a 1000-mL round-bottom flask was heatedunder reflux overnight in an oil bath. The resulting mixture wasconcentrated under vacuum; the pH value was adjusted to 7-8 with aqueoussodium bicarbonate (saturated), and the solution extracted with 4×100 mLof dichloromethane. The organic layers were combined, dried overanhydrous sodium sulfate and concentrated under vacuum, giving 2 g (78%)of methyl 3-bromo-2-phenylquinoxaline-6-carboxylate as a white solid.LC-MS (ES, m/z): 343 [M+H]⁺. ¹H-NMR (300 MHz, DMSO-d₆) 8.620-8.615 (d,J=1.5 Hz, 1H), 8.38-8.35 (q, J=3.3 Hz, 1H), 8.28-8.25 (d, J=8.7 Hz, 1H),7.85-7.82 (q, J=6 Hz, 2H), 7.60-7.58 (t, J=2.4 Hz, 3H), 3.99 (s, 3H).

-   -   wherein R₁ and R₂ are each independently chosen from alkyl,        cycloalkyl, heterocycloalkyl, aryl, heteroaryl, and amino any of        which may be optionally substituted; and R₃ is chosen from        hydrogen and optionally substituted alkyl.

The invention is further illustrated by the following examples, whichcan be made by the methods described herein or by one skilled in the artwithout undue experimentation, or can be purchased from commercialsources. Throughout the experimental protocols, the followingabbreviations may be used. The list below is provided for convenienceand is not intended to be inclusive.

Abbreviation/ Acronym Meaning Ar Aryl Pd₂(dba)₃Tris(dibenzylideneacetone)dipalladium(0) BINAP2,2′-bis(diphenylphosphino)-1,1′-binaphthyl NaOt-Bu Sodium t-Butoxide PEPetroleum Ether EA Ethyl Acetate DCM Dichloromethane TFA TrifluoroaceticAcid AcOH Acetic Acid DMF N,N-Dimethylformamide DIEAN,N-Diisopropylethylamine MeOH Methanol THF Tetrahydrofuran BOCN-t-butoxycarbonyl Tol Toluene DMSO Dimethyl Sulfoxide PCy3Tricyclohexylphosphine TLC Thin Layer Chromatography X-Phos2-Dicyclohexylphosphino-2′,4′,6′- triisopropylbiphenyl DDQ2,3-dichloro-5,6-dicyanobenzoquinone

EXAMPLE 12-Phenyl-3-(4-(4-(trifluoromethyl)phenyl)piperazin-1-yl)quinoxaline-6-carboxylicacid

Step 1. t-Butyl 4-(4-(trifluoromethyl)phenyl)piperazine-1-carboxylate

t-Butyl piperazine-1-carboxylate (1.52 g, 8.17 mmol, 2.00 equiv),1-bromo-4-(trifluoromethyl)benzene (1 g, 4.10 mmol, 1.00 equiv), BINAP(124 mg, 0.40 mmol, 0.10 equiv), Pd₂(dba)₃ (184 mg, 0.20 mmol, 0.05equiv), NaOt-Bu (1.2 g, 12.50 mmol, 3.00 equiv), and toluene (15 mL)were combined in a 100-mL round-bottom flask, stirred overnight at 100°C. in an oil bath, and concentrated under vacuum. Purification by silicagel column with PE/EA (50:1) yielded 1.06 g (78%) of t-butyl4-(4-(trifluoromethyl)phenyl)piperazine-1-carboxylate as a yellow solid.

LC-MS (ES, m/z): 331 [M+H]+

Step 2. 1-(4-(Trifluoromethyl)phenyl)piperazine

A solution of t-butyl4-(4-(trifluoromethyl)phenyl)piperazine-1-carboxylate (1.06 g, 3.21mmol, 1.00 equiv) in dichloromethane (10 mL) and trifluoroacetic acid (6mL) was placed in a 50-mL round-bottom flask and stirred for 2 h at 30°C. in an oil bath. The pH value of the solution was adjusted to 7-8 withsaturated aqueous sodium bicarbonate. The resulting solution wasextracted with 4×30 mL of dichloromethane and the organic layerscombined and dried over anhydrous sodium sulfate, followed by filtrationto remove the solids. The resulting solution was concentrated undervacuum, resulting in 740 mg (crude) of1-(4-(trifluoromethyl)phenyl)piperazine as a yellow solid.

LC-MS (ES, m/z): 231 [M+H]+

Step 3. Methyl2-phenyl-3-(4-(4-(trifluoromethyl)phenyl)piperazin-1-yl)quinoxaline-6-carboxylate

A solution of methyl 3-bromo-2-phenylquinoxaline-6-carboxylate (150 mg,0.44 mmol, 1.00 equiv) in DMF (8 mL),1-(4-(trifluoromethyl)phenyl)piperazine (202 mg, 0.88 mmol, 2.00 equiv),DIEA (170.3 mg, 1.32 mmol, 3.00 equiv) were placed in a 20-mL sealedtube and stirred overnight at 100° C. in an oil bath. The reaction wasthen quenched by the addition of water. The resulting solution wasextracted with 4×50 mL of ethyl acetate and the organic layers combinedand dried over anhydrous sodium sulfate followed by filtration to removesolids. The resulting mixture was concentrated under vacuum, resultingin 177.4 mg (78%) of methyl2-phenyl-3-(4-(4-(trifluoromethyl)phenyl)piperazin-1-yl)quinoxaline-6-carboxylateas a yellow solid.

LC-MS (ES, m/z): 492 [M+H]+

Step 4.2-Phenyl-3-(4-(4-(trifluoromethyl)phenyl)piperazin-1-yl)quinoxaline-6-carboxylicacid

A solution of methyl2-phenyl-3-(4-(4-(trifluoromethyl)phenyl)piperazin-1-yl)quinoxaline-6-carboxylate(137.7 mg, 0.28 mmol, 1.00 equiv) in methanol/THF (1:1) (10 mL), andsodium hydroxide (56 mg, 1.40 mmol, 5.00 equiv) in water (3 mL) wereplaced in a 50-mL round bottom flask and stirred for 2 h at 40° C. in anoil bath. The mixture was concentrated by vacuum and filtered. Theresulting solution was concentrated under vacuum, and the resultingsolid washed with DCM/MeOH (5:1) resulting in 45 mg (33%) of2-phenyl-3-(4-(4-(trifluoromethyl)phenyl)piperazin-1-yl)quinoxaline-6-carboxylicacid as a yellow solid.

LC-MS (ES, m/z): 478 [M+H]+

¹H-NMR (300 MHz, DMSO, ppm) δ 13.37 (1H, s), 8.341 (1H, s), 8.029 (4H,s), 7.578, 7.566 (4H, d, J=6.3 Hz), 7.528, 7.499 (2H, d, J=8.7 Hz),7.101, 7.072 (2H, d, J=8.7 Hz), 3.367 (8H, s).

EXAMPLE 22-Phenyl-3-(4-(pyridin-2-yl)piperazin-1-yl)quinoxaline-6-carboxylic acid

Step 1. t-Butyl 4-(pyridin-2-yl)piperazine-1-carboxylate

A solution of 2-bromopyridine (1.0 g, 6.33 mmol, 1.00 equiv), t-butylpiperazine-1-carboxylate (2.35 g, 12.62 mmol, 2.00 equiv), BINAP (196mg, 0.63 mmol, 0.10 equiv), Pd₂(dba)₃ (290 mg, 0.32 mmol, 0.05 equiv),and NaOt-Bu (1.89 g, 18.90 mmol, 3.00 equiv) in toluene (20 mL) wasplaced in a 100-mL round bottom flask under an inert atmosphere andstirred overnight at 100° C. in an oil bath. The resulting mixture wasconcentrated under vacuum. Purification by silica gel column (ethylacetate/petroleum ether (1:40)) yielded 1.4 g (84%) of t-butyl4-(pyridin-2-yl)piperazine-1-carboxylate as a yellow solid.

Step 2. 1-(Pyridin-2-yl)piperazine

A solution of t-butyl 4-(pyridin-2-yl)piperazine-1-carboxylate (500 mg,1.90 mmol, 1.00 equiv) in DCM/CF₃COOH (10/3 mL) was placed in a 50-mLround bottom flask and stirred for 1 h at 30° C. in an oil bath. The pHvalue of the solution was adjusted to 9 with aqueous sodium hydroxide(IM), then extracted with 3×10 mL of dichloromethane. The organic layerscombined, dried over anhydrous sodium sulfate, and filtered to removesolids. The resulting solution was concentrated under vacuum, yielding300 mg (97%) of 1-(pyridin-2-yl)piperazine as yellow oil.

Step 3. Methyl2-phenyl-3-(4-(pyridin-2-yl)piperazin-1-yl)quinoxaline-6-carboxylate

A solution of methyl 3-bromo-2-phenylquinoxaline-6-carboxylate (50 mg,0.15 mmol, 1.00 equiv), 1-(pyridin-2-yl)piperazine (50 mg, 0.31 mmol,2.00 equiv), and DIEA (100 mg, 0.78 mmol, 3.00 equiv) in DMF (10 mL) wasplaced in a 20-mL sealed tube under an inert atmosphere and stirredovernight at 100° C. in an oil bath and then concentrated under vacuum.Purification via silica gel column (ethyl acetate/petroleum ether(1:10)) yielded 68 mg (crude) of methyl2-phenyl-3-(4-(pyridin-2-yl)piperazin-1-yl)quinoxaline-6-carboxylate asa yellow solid

Step 4.2-Phenyl-3-(4-(pyridin-2-yl)piperazin-1-yl)quinoxaline-6-carboxylic acid

A solution of methyl2-phenyl-3-(4-(pyridin-2-yl)piperazin-1-yl)quinoxaline-6-carboxylate(100 mg, 0.24 mmol, 1.00 equiv) and sodium hydroxide (47 mg, 1.18 mmol,5.00 equiv) in methanol (10 mL) was placed in a 100-mL round bottomflask and stirred for 2 h at 50° C. in an oil bath. The pH of thesolution was adjusted to 4-5 with hydrochloric acid (1 M), followed byextractions with 3×10 mL of dichloromethane. The organic layers werecombined and concentrated under vacuum yielding 80 mg (83%) of2-phenyl-3-(4-(pyridin-2-yl)piperazin-1-yl)quinoxaline-6-carboxylic acidas a yellow solid.

LC-MS (ES, m/z): 412 [M+H]+

¹H-NMR (300 MHz, CDCl₃, ppm) δ 8.507 (s, 1H), 7.970-8.159 (m, 5H),7.574-7.617 (m, 4H), 6.846-6.875 (m, 1H), 6.694-6.733 (m, 1H),3.540-3.559 (m, 4H), 3.437-3.454 (m, 4H).

EXAMPLE 33-(4-(3-Chlorophenyl)piperazin-1-yl)-2-phenylquinoxaline-6-carboxylicacid

Step 1. t-Butyl 4-(3-chlorophenyl)piperazine-1-carboxylate

A solution of t-butyl piperazine-1-carboxylate (1.96 g, 10.54 mmol, 2.00equiv), 1-bromo-3-chlorobenzene (1 g, 5.26 mmol, 1.00 equiv), BINAP (330mg, 0.53 mmol, 0.10 equiv), Pd₂(dba)₃ (243.8 mg, 0.27 mmol, 0.05 equiv),NaOt-Bu (1.59 g, 16.56 mmol, 3.00 equiv), and toluene (17 mL) was placedin a 100-mL round bottom flask, stirred overnight at 100° C. in an oilbath, and concentrated under vacuum. Purification via silica gel column(PE/EA (50:1)) yielded 1.3 g (83%) of t-butyl4-(3-chlorophenyl)piperazine-1-carboxylate as a yellow solid.

LC-MS (ES, m/z): 297 [M+H]⁺

Step 2. 1-(3-Chlorophenyl)piperazine

A solution of t-butyl 4-(4-methoxyphenyl)piperazine-1-carboxylate (1.3g, 4.39 mmol, 1.00 equiv) in dichloromethane (11 mL) and trifluoroaceticacid (6 mL) was placed in a 50-mL round bottom flask and stirred for 3 hat 20° C. in an oil bath. The solution was adjusted to a pH value of 7-8with a saturated aqueous solution of sodium bicarbonate, and extractedwith 6×15 mL of dichloromethane. The organic layers combined and driedover anhydrous sodium sulfate, filtered to remove solids, andconcentrated under vacuum yielding 430 mg (50%) of1-(3-chlorophenyl)piperazine as a yellow solid.

LC-MS (ES, m/z): 197 [M+H]⁺

Step 3. Methyl3-(4-(3-chlorophenyl)piperazin-1-yl)-2-phenylquinoxaline-6-carboxylate

A solution of methyl 3-bromo-2-phenylquinoxaline-6-carboxylate (150 mg,0.44 mmol, 1.00 equiv), 1-(3-chlorophenyl)piperazine (172.5 mg, 0.88mmol, 2.00 equiv), and DIEA (170.3 mg, 1.32 mmol, 3.00 equiv) in DMF (4mL) was placed in a 20-mL sealed tube and stirred overnight at 100° C.in an oil bath, then quenched with water. The resulting solution wasextracted with 6×20 mL of ethyl acetate, the organic layers combined anddried over anhydrous sodium sulfate, filtered to remove solids, andconcentrated under vacuum. Purification via silica gel column (PE/EA(30:1)) yielded 186.7 mg (89%) of methyl3-(4-(3-chlorophenyl)piperazin-1-yl)-2-phenylquinoxaline-6-carboxylateas a yellow solid.

LC-MS (ES, m/z): 459 [M+H]⁺

Step 4.3-(4-(3-Chlorophenyl)piperazin-1-yl)-2-phenylquinoxaline-6-carboxylicacid

A solution of methyl3-(4-(3-chlorophenyl)piperazin-1-yl)-2-phenylquinoxaline-6-carboxylate(186.7 mg, 0.41 mmol, 1.00 equiv) and sodium hydroxide (82 mg, 2.05mmol, 5.00 equiv) in tetrahydrofuran/MeOH (1:1) (25 mL) was placed in a50-mL round bottom flask, stirred for 8 h at 50° C. in an oil bath, andthen concentrated under vacuum. This resulted in 177.7 mg (95%) of3-(4-(3-chlorophenyl)piperazin-1-yl)-2-phenylquinoxaline-6-carboxylicacid as a yellow solid.

LC-MS (ES, m/z): 445 [M+H]+

¹H-NMR (300 MHz, DMSO, ppm) δ 8.340 (1H, s), 8.029 (4H, s), 7.587, 7.565(3H, d, J=6.6 Hz), 7.217, 7.190 (1H, d, J=8.1 Hz), 6.972, 6.935 (2H, d,J=11.1 Hz), 6.818, 6.789 (2H, d, J=8.7 Hz), 3.3.246 (4H, s).

EXAMPLE 4 3-(4-Methylpiperazin-1-yl)-2-phenylquinoxaline-6-carboxylicacid

Step 1. Methyl3-(4-methylpiperazin-1-yl)-2-phenylquinoxaline-6-carboxylate

Methyl 3-bromo-2-phenylquinoxaline-6-carboxylate (150 mg, 0.44 mmol,1.00 equiv) in DMSO (8 mL) and 1-methylpiperazine (90 mg, 0.90 mmol,2.00 equiv) were stirred for 2 hours at 125° C. in an oil bath in a20-mL sealed tube. The resulting solution was diluted with 20 ml ofDCM/H₂O (1:1), extracted with 4×40 mL of DCM, and the organic layerscombined. The mixture was dried over Na₂SO₄, filtered to remove solids,and then concentrated under vacuum, resulting in 200 mg (crude) ofmethyl 3-(4-methylpiperazin-1-yl)-2-phenylquinoxaline-6-carboxylate as abrown solid.

LC-MS (ES, m/z): 363 [M+H]+

Step 2. 3-(4-Methylpiperazin-1-yl)-2-phenylquinoxaline-6-carboxylic acid

Solutions of methyl3-(4-methylpiperazin-1-yl)-2-phenylquinoxaline-6-carboxylate (249.7 mg,0.55 mmol, 1.00 equiv.) in THF/MeOH (1:1) (20 mL) and sodium hydroxide(138 mg, 3.45 mmol, 5.00 equiv) in water (1.5 mL) were placed in a 50-mLround bottom flask, stirred for 3 hrs at 30° C. in an oil bath,concentrated under vacuum, and washed with DCM. This resulted in 90 mg(45%) of 3-(4-methylpiperazin-1-yl)-2-phenylquinoxaline-6-carboxylicacid as a yellow solid.

LC-MS (ES, m/z): 348 [M+H]+

¹H-NMR (300 MHz, DMSO, ppm) 8.355 (1H, s), 8.083-8.017 (4H, t),8.585-8.572 (3H, d, J=3.9 Hz), 3.341-3.202 (8H, d, J=41.7 Hz), 2.737(3H, s).

EXAMPLE 5 2-Phenyl-3-(piperazin-1-yl)quinoxaline-6-carboxylic acid

Step 1. Methyl 2-phenyl-3-(piperazin-1-yl)quinoxaline-6-carboxylate

A solution of methyl 3-bromo-2-phenylquinoxaline-6-carboxylate (150 mg,0.44 mmol, 1.00 equiv) and piperazine (77.4 mg, 0.90 mmol, 2.00 equiv)in DMSO (8 mL) was placed in a 20-mL sealed tube, stirred for 3 hrs at125° C. in an oil bath, and then quenched by the addition of 50 mL ofwater. The resulting solution was extracted with 6×50 mL ofdichloromethane, the organic layers combined and dried over anhydroussodium sulfate, and the solution filtered to remove solids.Concentration under vacuum yielded 160 mg (91%) of methyl2-phenyl-3-(piperazin-1-yl)quinoxaline-6-carboxylate as a yellow solid.

LC-MS (ES, m/z): 348 [M+H]+

Step 2. 2-Phenyl-3-(piperazin-1-yl)quinoxaline-6-carboxylic acid

Solutions of methyl 2-phenyl-3-(piperazin-1-yl)quinoxaline-6-carboxylate(160 mg, 0.42 mmol, 1.00 equiv.) in THF/MeOH (1:1) (20 mL) and sodiumhydroxide (91.9 mg, 2.30 mmol, 5.00 equiv) in water (1.5 mL) were placedin a 50-mL round bottom flask, stirred for 3 hrs at 30° C. in an oilbath, and then concentrated under vacuum. The residue was dissolved in 4mL of DMSO and purified via silica gel column (DCM/MeOH (5:1)) yielding42 mg (29%) of 2-phenyl-3-(piperazin-1-yl)quinoxaline-6-carboxylic acidas a yellow solid.

LC-MS (ES, m/z): 334 [M+H]+

¹H-NMR (300 MHz, DMSO, ppm) 8.346-8.342 (1H, d, H=1.2 Hz), 8.150 (1H,s), 8.054-8.007 (3H, q), 7.584-7.560 (3H, t), 3.420 (4H, s), 3.112 (4H,s).

EXAMPLE 6 2-Phenyl-3-(4-phenylpiperazin-1-yl)quinoxaline-6-carboxylicacid

Step 1. t-Butyl 4-phenylpiperazine-1-carboxylate

A solution of 1-bromobenzene (1 g, 6.37 mmol, 1.00 equiv), t-butylpiperazine-1-carboxylate (2.35 g, 12.62 mmol, 2.00 equiv), BINAP (196mg, 0.63 mmol, 0.10 equiv), Pd₂(dba)₃ (290 mg, 0.32 mmol, 0.05 equiv),and NaOt-Bu (1.89 g, 18.90 mmol, 3.00 equiv) in toluene (20 mL) wasplaced in a 100-mL 3-necked round bottom flask and stirred overnight at100° C. in an oil bath under an inert atmosphere. The resulting mixturewas concentrated under vacuum and purified via silica gel column (ethylacetate/petroleum ether (1:40)) yielding 1.3 g (78%) of t-butyl4-phenylpiperazine-1-carboxylate as a yellow solid.

Step 2. 1-Phenylpiperazine

A solution of t-butyl 4-phenylpiperazine-1-carboxylate (500 mg, 1.91mmol, 1.00 equiv) in DCM/CF₃COOH (10/3 mL) was placed in a 50-mL roundbottom flask and stirred for 1 h at 30° C. in an oil bath. The pH valueof the solution was adjusted to 9 with aqueous sodium hydroxide (1 M),and the solution was extracted with 3×10 mL of dichloromethane, theorganic layers combined and dried over anhydrous sodium sulfate. Solidswere removed via filtration, and the resulting solution concentratedunder vacuum yielding 300 mg (97%) of 1-phenylpiperazine as yellow oil.

Step 3. Methyl2-phenyl-3-(4-phenylpiperazin-1-yl)quinoxaline-6-carboxylate

To a solution of methyl 3-bromo-2-phenylquinoxaline-6-carboxylate (50mg, 0.15 mmol, 1.00 equiv) in DMF (10 mL) was added 1-phenylpiperazine(50 mg, 0.31 mmol, 2.00 equiv) and DIEA (100 mg, 0.78 mmol, 5.3 equiv).The resulting solution was placed in a 20-mL sealed tube, stirredovernight at 100° C. in an oil bath, then concentrated under vacuum.Purification via silica gel column (ethyl acetate/petroleum ether(1:10)) yielded 70 mg (crude) of methyl2-phenyl-3-(4-phenylpiperazin-1-yl)quinoxaline-6-carboxylate as a yellowsolid.

Step 4. 2-Phenyl-3-(4-phenylpiperazin-1-yl)quinoxaline-6-carboxylic acid

A solution of methyl2-phenyl-3-(4-phenylpiperazin-1-yl)quinoxaline-6-carboxylate (100 mg,0.24 mmol, 1.00 equiv) and sodium hydroxide (47 mg, 1.18 mmol, 5.00equiv) in methanol (10 mL) was placed in a 100-mL round bottom flask andstirred for 2 h at 50° C. in an oil bath. The pH value of the solutionwas adjusted to 4-5 with hydrochloric acid (1 M). The resulting solutionwas extracted with 3×10 mL of dichloromethane, and the organic layerscombined and concentrated under vacuum, yielding 70 mg (72%) of2-phenyl-3-(4-phenylpiperazin-1-yl)quinoxaline-6-carboxylic acid as ayellow solid.

LC-MS (ES, m/z): 411 [M+H]+

¹H-NMR (300 MHz, CDCl₃, ppm) δ 8.472 (s, 1H), 8.118-8.147 (m, 1H),8.009-8.041 (m, 2H), 7.923-7.952 (m, 1H), 7.536-7.596 (m, 3H),7.218-7.271 (m, 2H), 6.961-6.987 (m, 2H), 6.830-6.879 (m, 1H),3.434-3.466 (m, 4H), 3.170-3.202 (m, 4H).

EXAMPLE 72-Phenyl-3-(4-(4-(trifluoromethyl)phenyl)piperidin-1-yl)quinoxaline-6-carboxylicacid

Step 1. 4-(4-(Trifluoromethyl)phenyl)pyridine

A solution of 1-bromo-4-(trifluoromethyl)benzene (1.0 g, 4.44 mmol, 1.00equiv), pyridin-4-ylboronic acid (820 mg, 6.67 mmol, 1.50 equiv), PCy₃(156 mg, 0.56 mmol, 0.14 equiv), Pd₂(dba)₃ (220 mg, 0.24 mmol, 0.06equiv), and K₃PO₄ (2.5 g, 11.79 mmol, 3.00 equiv) in 1,4-dioxane (10 mL)was placed in a 20-mL sealed tube under inert atmosphere stirredovernight at 100° C. in an oil bath, and then concentrated under vacuum.Purification via silica gel column (ethyl acetate/petroleum ether(1:20)) yielded 1.2 g (crude) of 4-(4-(trifluoromethyl)phenyl)pyridineas a yellow solid.

Step 2. 4-(4-(Trifluoromethyl)phenyl)piperidine

A suspension of 4-(4-(trifluoromethyl)phenyl)pyridine (500 mg, 2.24mmol, 1.00 equiv), CF₃COOH (1.27 g, 11.14 mmol, 5.00 equiv), andpalladium carbon (100 mg, 5%) in methanol (50 mL) was hydrogenatedovernight under an atmosphere of H₂ (g) at 30° C. in an oil bath. Thereaction mixture was filtered and washed with methanol and concentratedin vacuo. The pH value of the solution was adjusted to 8-9 with aqueoussodium hydroxide (1 M). The resulting solution was extracted with 3×20mL of dichloromethane and the organic layers combined and concentratedunder vacuum, yielding 350 mg (68%) of4-(4-(trifluoromethyl)phenyl)piperidine as brown oil.

LC-MS (ES, m/z) [M+H]⁺: 230

Step 3. Methyl2-phenyl-3-(4-(4-(trifluoromethyl)phenyl)piperidin-1-yl)quinoxaline-6-carboxylate

A solution of 4-(4-(trifluoromethyl)phenyl)piperidine (200 mg, 0.87mmol, 2.00 equiv), methyl 3-bromo-2-phenylquinoxaline-6-carboxylate (150mg, 0.44 mmol, 1.00 equiv), and DIEA (169 mg, 1.31 mmol, 3.00 equiv) inDMF (10 mL) was placed in a 20-mL sealed tube and stirred overnight at100° C. in an oil bath. The resulting mixture was concentrated undervacuum and purified via silica gel column (ethyl acetate/petroleum ether(1:20)), yielding 180 mg (84%) of methyl2-phenyl-3-(4-(4-(trifluoromethyl)phenyl)piperidin-1-yl)quinoxaline-6-carboxylateas a yellow solid.

Step 4.2-Phenyl-3-(4-(4-(trifluoromethyl)phenyl)piperidin-1-yl)quinoxaline-6-carboxylicacid

A solution of methyl2-phenyl-3-(4-(4-(trifluoromethyl)phenyl)piperidin-1-yl)quinoxaline-6-carboxylate(50 mg, 0.10 mmol, 1.00 equiv) and sodium hydroxide (20 mg, 0.50 mmol,5.00 equiv) in methanol (10 mL) was placed in a 50-mL round bottom flaskand stirred for 2 h at 50° C. in an oil bath. The pH value of thesolution was adjusted to 4-5 with aqueous sodium hydroxide (1 M). Theresulting solution was extracted with 3×10 mL of dichloromethane, andthe organic layers combined, concentrated under vacuum, and purified byprep-TLC (DCM:CH₃OH 10:1) yielding 25 mg (51%) of2-phenyl-3-(4-(4-(trifluoromethyl)phenyl)piperidin-1-yl)quinoxaline-6-carboxylicacid as a white solid.

LC-MS (ES, m/z): 478 [M+H]+

¹H-NMR (300 MHz, CDCl₃, ppm) δ 8.319 (s, 1H), 7.964-8.056 (m, 4H),7.496-7.688 (m, 7H), 3.862-3.906 (m, 2H), 2.862-2.934 (m, 4H), 1.770 (m,3H).

EXAMPLE 83-(4-(4-Chlorophenyl)piperazin-1-yl)-2-phenylquinoxaline-6-carboxylicacid

Step 1. t-Butyl 4-(4-chlorophenyl)piperazine-1-carboxylate

A suspension of 1-bromo-4-chlorobenzene (500 mg, 2.63 mmol, 1.00 equiv),t-butyl piperazine-1-carboxylate (725 mg, 3.90 mmol, 1.50 equiv), BINAP(48.6 mg, 0.08 mmol, 0.03 equiv), Pd₂(dba)₃ (23.9 mg, 0.03 mmol, 0.01equiv), and NaOt-Bu (780 mg, 8.12 mmol, 3.00 equiv) in toluene (20 mL)was placed in a 50-mL round bottom flask, stirred overnight at 100° C.in an oil bath, then concentrated under vacuum. Purification via silicagel column (PE/EA (50:1)) yielded 360.6 mg (46%) of t-butyl4-(4-chlorophenyl)piperazine-1-carboxylate as a yellow solid.

LC-MS (ES, m/z): 297 [M+H]+

Step 2. 1-(4-Chlorophenyl)piperazine

Trifluoroacetic acid (3 mL) was added dropwise with stirring at 0° C. toa solution of t-butyl 4-(4-chlorophenyl)piperazine-1-carboxylate (360.6mg, 1.21 mmol, 1.00 equiv) in dichloromethane (12 mL). The resultingsolution was stirred for 3 h at 20° C. in an oil bath. The pH value ofthe solution was adjusted to 7-8 with a saturated solution of sodiumbicarbonate. The resulting solution was extracted with 6×20 mL ofdichloromethane, the organic layers combined and dried over anhydroussodium sulfate and concentrated under vacuum. This resulted in 264.5 mg(102%) of 1-(4-chlorophenyl)piperazine as a yellow solid.

LC-MS (ES, m/z): 197 [M+H]+

Step 3. Methyl3-(4-(4-chlorophenyl)piperazin-1-yl)-2-phenylquinoxaline-6-carboxylate

A solution of methyl 3-bromo-2-phenylquinoxaline-6-carboxylate (150 mg,0.44 mmol, 1.00 equiv), 1-(4-chlorophenyl)piperazine (172.5 mg, 0.88mmol, 5.00 equiv), and DIEA (170.3 mg, 1.32 mmol, 3.00 equiv) in DMF (4mL) was placed in a 8-mL sealed tube, stirred overnight at 100° C. in anoil bath, then concentrated under vacuum. Purification via silica gelcolumn (ethyl acetate/petroleum ether (1:50)) afforded 153.4 mg (69%) ofmethyl3-(4-(4-chlorophenyl)piperazin-1-yl)-2-phenylquinoxaline-6-carboxylateas a yellow solid.

LC-MS (ES, m/z): 459 [M+H]+

Step 4.3-(4-(4-Chlorophenyl)piperazin-1-yl)-2-phenylquinoxaline-6-carboxylicacid

A solution of methyl3-(4-(4-chlorophenyl)piperazin-1-yl)-2-phenylquinoxaline-6-carboxylate(153.4 mg, 0.33 mmol, 1.00 equiv) and sodium hydroxide (66 mg, 1.65mmol, 5.00 equiv) in tetrahydrofuran/MeOH (1:1) (12 mL) was placed in a50-mL round bottom flask and stirred for 5 h at 50° C. in an oil bath.The pH value of the solution was adjusted to 3-4 with 1N hydrochloricacid, then concentrated under vacuum. The resulting solid was washedwith methanol affording 47 mg (31%) of3-(4-(4-chlorophenyl)piperazin-1-yl)-2-phenylquinoxaline-6-carboxylicacid as a yellow solid.

LC-MS (ES, m/z): 445 [M+H]+

¹H-NMR (300 MHz, DMSO, ppm) δ 13.305 (1H, s), 8.342 (1H, s), 8.031 (4H,s), 7.585, 7.566 (3H, d, J=5.7 Hz), 7.256, 7.228 (2H, d, J=8.4 Hz),6.984, 6.956 (2H, d, J=8.4 Hz), 3.359 (4H, s), 3.204 (4H, s).

EXAMPLE 93-(4-(4-Methoxyphenyl)piperazin-1-yl)-2-phenylquinoxaline-6-carboxylicacid

Step 1. t-Butyl 4-(4-methoxyphenyl)piperazine-1-carboxylate

A suspension of t-butyl piperazine-1-carboxylate (2 g, 10.75 mmol, 2.00equiv), 1-bromo-4-methoxybenzene (1 g, 5.38 mmol, 1.00 equiv), X-phos(257.2 mg, 0.54 mmol, 0.10 equiv), Pd₂(dba)₃ (248.4 mg, 0.27 mmol, 0.05equiv), and NaOt-Bu (1.62 g, 16.88 mmol, 3.00 equiv) in toluene (15 mL)was placed in a 100-mL round bottom flask, stirred overnight at 100° C.in an oil bath, then concentrated under vacuum. Purification via silicagel column (PE/EA (50:1)) yielded 1.412 g (81%) of t-butyl4-(4-methoxyphenyl)piperazine-1-carboxylate as a yellow solid.

LC-MS (ES, m/z): 293 [M+H]+

Step 2. 1-(4-Methoxyphenyl)piperazine

A solution of t-butyl 4-(4-methoxyphenyl)piperazine-1-carboxylate (1.412g, 4.84 mmol, 1.00 equiv) in dichloromethane (17 mL) and trifluoroaceticacid (6 mL) was placed in a 50-mL round bottom flask and stirred for 2 hat 20° C. in an oil bath. The pH of the solution was adjusted to 7-8with saturated aqueous sodium bicarbonate. The resulting mixture wasconcentrated under vacuum yielding 0.92 g (65%) of1-(4-methoxyphenyl)piperazine as a yellow solid.

LC-MS (ES, m/z): 193 [M+H]+

Step 3. Methyl3-(4-(4-methoxyphenyl)piperazin-1-yl)-2-phenylquinoxaline-6-carboxylate

A solution of methyl 3-bromo-2-phenylquinoxaline-6-carboxylate (200 mg,0.58 mmol, 1.00 equiv), 1-(4-methoxyphenyl)piperazine (230.4 mg, 1.20mmol, 2.00 equiv) and DIEA (232.3 mg, 1.80 mmol, 3.00 equiv) in DMF (6mL) was placed in a 20-mL sealed tube and stirred overnight at 100° C.in an oil bath, then concentrated under vacuum. Purification viaprep-HPLC yielded 117.1 mg (42%) of methyl3-(4-(4-methoxyphenyl)piperazin-1-yl)-2-phenylquinoxaline-6-carboxylateas a yellow solid.

LC-MS (ES, m/z): 455 [M+H]+

Step 4.3-(4-(4-Methoxyphenyl)piperazin-1-yl)-2-phenylquinoxaline-6-carboxylicacid

A solution of methyl3-(4-(4-methoxyphenyl)piperazin-1-yl)-2-phenylquinoxaline-6-carboxylate(117.1 mg, 0.26 mmol, 1.00 equiv) and sodium hydroxide (51.6 mg, 1.29mmol, 5.00 equiv) in methanol (15 mL) was placed in a 50-mL round bottomflask and stirred for 5 h at 50° C. in an oil bath. The solution wasadjusted to a pH of 3-4 with 1N hydrochloric acid, and then concentratedunder vacuum. The resulting solids were washed with methanol yielding 80mg (70%) of3-(4-(4-methoxyphenyl)piperazin-1-yl)-2-phenylquinoxaline-6-carboxylicacid as a yellow solid.

LC-MS (ES, m/z): 441 [M+H]+

¹H-NMR (300 MHz, DMSO, ppm) δ 13.330 (1H, s), 8.331 (1H, s), 8.019 (4H,s), 7.579, 7.557 (3H, d, J=6.6 Hz), 6.922-6.802 (4H, q, J=9 Hz), 3.683(4H, s), 3.068 (4H, s).

EXAMPLE 103-(4-(3-Chlorophenyl)piperidin-1-yl)-2-phenylquinoxaline-6-carboxylicacid

Step 1. Methyl3-(4-(3-chlorophenyl)piperidin-1-yl)-2-phenylquinoxaline-6-carboxylate

A solution of methyl 3-bromo-2-phenylquinoxaline-6-carboxylate (150 mg,0.44 mmol, 1.00 equiv), 4-(3-chlorophenyl)piperidine hydrochloride(204.2 mg, 0.88 mmol, 2.00 equiv), and DIEA (194.8 mg, 1.51 mmol, 5.00equiv) in DMF (4 mL) was placed in an 8-mL sealed tube and stirredovernight at 100° C. in an oil bath. The reaction was then quenched bythe addition of water, then concentrated under vacuum. Purification viasilica gel column (ethyl acetate/petroleum ether (1:100)) yielded 143.5mg (64%) of methyl3-(4-(3-chlorophenyl)piperidin-1-yl)-2-phenylquinoxaline-6-carboxylateas a yellow solid.

LC-MS (ES, m/z): 457 [M+H]+

Step 2.3-(4-(3-Chlorophenyl)piperidin-1-yl)-2-phenylquinoxaline-6-carboxylicacid

To a solution of methyl3-(4-(3-chlorophenyl)piperidin-1-yl)-2-phenylquinoxaline-6-carboxylate(143.5 mg, 0.29 mmol, 1.00 equiv, 91%) in methanol (15 mL) was added asolution of sodium hydroxide (62.8 mg, 1.57 mmol, 5.00 equiv) in water(2 mL) dropwise with stirring. The resulting solution was stirredovernight at 50° C. in an oil bath, then concentrated under vacuum. Theresulting solids were washed with methanol yielding 44 mg (34%) of3-(4-(3-chlorophenyl)piperidin-1-yl)-2-phenylquinoxaline-6-carboxylicacid as a yellow solid.

LC-MS (ES, m/z): 443 [M+H]+

¹H-NMR (300 MHz, DMSO, ppm) δ 13.272 (1H, s), 8.312 (1H, s), 8.050-8.000(4H, t), 7.611-7.528 (3H, t), 7.370-7.228 (4H, m) 3.941-3.864 (2H, t),2.907-2.717 (3H, m), 1.738-1.631 (4H, t).

EXAMPLE 113-(4-(4-Methoxyphenyl)piperidin-1-yl)-2-phenylquinoxaline-6-carboxylicacid

Step 1. Methyl3-(4-(4-methoxyphenyl)piperidin-1-yl)-2-phenylquinoxaline-6-carboxylate

A solution of methyl 3-chloro-2-phenylquinoxaline-6-carboxylate (150 mg,0.50 mmol, 1.00 equiv), 4-(4-methoxyphenyl)piperidine (191 mg, 1.00mmol, 2.00 equiv), and DIEA (194.8 mg, 1.51 mmol, 5.00 equiv) in DMF (4mL) was placed in an 8-mL sealed tube and stirred overnight at 100° C.in an oil bath. The reaction was then quenched by the addition of water,and the resulting mixture was concentrated under vacuum. Purificationvia silica gel column (ethyl acetate/petroleum ether (1:50)) yielded179.6 mg (63%) of methyl3-(4-(4-methoxyphenyl)piperidin-1-yl)-2-phenylquinoxaline-6-carboxylateas a yellow solid.

LC-MS (ES, m/z): 454 [M+H]⁺

Step 2.3-(4-(4-Methoxyphenyl)piperidin-1-yl)-2-phenylquinoxaline-6-carboxylicacid

To a solution of methyl3-(4-(4-methoxyphenyl)piperidin-1-yl)-2-phenylquinoxaline-6-carboxylate(179.6 mg, 0.36 mmol, 1.00 equiv, 90%) in methanol (17 mL) was added asolution of sodium hydroxide (80 mg, 2.00 mmol, 5.00 equiv) in water (2mL) dropwise with stirring. The resulting solution was stirred for 7 hat 50° C. in an oil bath, then the pH of the solution was adjusted to3-4 with 1N hydrochloric acid. The resulting mixture was concentratedunder vacuum, followed by washing with methanol yielding 81.9 mg (50%)of3-(4-(4-methoxyphenyl)piperidin-1-yl)-2-phenylquinoxaline-6-carboxylicacid as a yellow solid.

LC-MS (ES, m/z): 440 [M+H]+

¹H-NMR (300 MHz, DMSO, ppm) δ 8.302 (1H, s), 8.035-7.991 (4H, m),7.607-7.519 (3H, m), 7.177, 7.148 (2H, d, J=8.7 Hz), 6.873-6.844 (2H, d,J=8.7 Hz), 3.889, 3.846 (2H, d, J=12.9 Hz), 3.717 (3H, s), 2.899-2.825(2H, t), 2.661-2.610 (1H, t), 1.732-1.619 (4H, m).

EXAMPLE 12 2-Phenyl-3-(piperidin-1-yl)quinoxaline-6-carboxylic acid

Into a 8-mL sealed tube, were placed a solution of methyl3-bromo-2-phenylquinoxaline-6-carboxylate (200 mg, 0.58 mmol, 1.00equiv) piperidine (149 mg, 1.75 mmol, 3.01 equiv), potassium carbonate(404 mg, 2.93 mmol, 5.02 equiv), H₂O (1 mL) and DMF (3 mL). Theresulting mixture was stirred for overnight at 100° C. The resultingmixture was concentrated under vacuum. The residue was dissolved in 20mL of H₂O. The pH value of the aqueous solution was adjusted to 5 withhydrogen chloride (1 mol/L). The resulting solids were collected byfiltration and washed with water and dried in an oven under reducedpressure. This resulted in 105 mg (54%) of2-phenyl-3-(piperidin-1-yl)quinoxaline-6-carboxylic acid as a yellowsolid.

LC-MS: (ES, m/z): 334 [M+H]⁺

¹H-NMR (300 MHz, DMSO, ppm): δ 8.28 (d, J=1.2 Hz, 1H), 8.02-7.94 (m,4H), 7.60-7.52 (m, 3H), 3.22 (s, 4H), 1.53 (s, 6H).

EXAMPLE 13 2-Phenyl-3-(4-phenylpiperidin-1-yl)quinoxaline-6-carboxylicacid

Step 1. Methyl2-phenyl-3-(4-phenylpiperidin-1-yl)quinoxaline-6-carboxylate

Into a 8-mL sealed tube, was placed methyl3-bromo-2-phenylquinoxaline-6-carboxylate (150 mg, 0.44 mmol, 1.00equiv), 4-phenylpiperidine (141.68 mg, 0.88 mmol, 2.00 equiv), DIEA(170.3 mg, 1.32 mmol, 3.00 equiv), N,N-dimethylformamide (4 mL). Theresulting solution was stirred overnight at 100° C. in an oil bath. Theresulting mixture was concentrated under vacuum. The residue was appliedonto a silica gel column with PE/EA (100:1). This resulted in 92.9 mg(49%) of methyl2-phenyl-3-(4-phenylpiperidin-1-yl)quinoxaline-6-carboxylate as a yellowsolid.

LC-MS: (ES, m/z): 424 [M+H]+

Step 2. 2-Phenyl-3-(4-phenylpiperidin-1-yl)quinoxaline-6-carboxylic acid

Into a 50-mL round-bottom flask, was placed a solution of methyl2-phenyl-3-(4-phenylpiperidin-1-yl)quinoxaline-6-carboxylate (92.9 mg,0.22 mmol, 1.00 equiv) in methanol (15 mL), a solution of sodiumhydroxide (44 mg, 1.10 mmol, 5.00 equiv) in water (1.5 mL). Theresulting solution was stirred overnight at 50° C. in an oil bath. ThepH value of the solution was adjusted to 3-4 with 1N hydrogen chloride.The resulting mixture was concentrated under vacuum. The resultingmixture was washed with methanol. This resulted in 85 mg (93%) of2-phenyl-3-(4-phenylpiperidin-1-yl)quinoxaline-6-carboxylic acid as ayellow solid.

LC-MS: (ES, m/z): 410 [M+H]+

¹H-NMR (300 MHz, DMSO, ppm): δ 13.291 (1H, s), 8.311 (1H, s),8.041-7.942 (4H, m), 7.611-7.503 (3H, m), 7.336-7.179 (5H, m), 3.903,3.861 (2H, d, J=12.6 Hz), 2.918-2.844 (2H, t), 2.708-2.676 (1H, t),1.733-1.628 (4H, m)

EXAMPLE 14 3-(Azepan-1-yl)-2-phenylquinoxaline-6-carboxylic acid

Step 1. Methyl 3-(azepan-1-yl)-2-phenylquinoxaline-6-carboxylate

Into a 8-mL sealed tube, was placed methyl3-bromo-2-phenylquinoxaline-6-carboxylate (150 mg, 0.44 mmol, 1.00equiv), HMI (87.27 mg, 0.88 mmol, 2.00 equiv), DIEA (170.3 mg, 1.32mmol, 3.00 equiv), N,N-dimethylformamide (4 mL). The resulting solutionwas stirred overnight at 100° C. in an oil bath. The solids werefiltered out. The resulting mixture was concentrated under vacuum. Theresidue was applied onto a silica gel column with ethylacetate/petroleum ether (1:100). This resulted in 132.4 mg (81%) ofmethyl 3-(azepan-1-yl)-2-phenylquinoxaline-6-carboxylate as a yellowsolid.

LC-MS: (ES, m/z): 362 [M+H]+

Step 2. 3-(Azepan-1-yl)-2-phenylquinoxaline-6-carboxylic acid

Into a 50-mL round-bottom flask, was placed a solution of methyl3-(azepan-1-yl)-2-phenylquinoxaline-6-carboxylate (132.4 mg, 0.37 mmol,1.00 equiv) in methanol (15 mL), a solution of sodium hydroxide (73.4mg, 1.83 mmol, 5.00 equiv) in water (2 mL). The resulting solution wasstirred overnight at 50° C. in an oil bath. The pH value of the solutionwas adjusted to 3-4 with 1N hydrogen chloride. The resulting mixture wasconcentrated under vacuum. The resulting mixture was washed withmethanol. This resulted in 80 mg (61%) of3-(azepan-1-yl)-2-phenylquinoxaline-6-carboxylic acid as a yellow solid.

LC-MS: (ES, m/z): 347 [M+H]⁺

¹H-NMR (300 MHz, DMSO, ppm): δ 13.204 (1H, s), 8.233 (1H, s),7.939-7.873 (2H, m), 7.743-7.712 (2H, m), 7.565-7.493 (3H, m),3.446-3.408 (4H, t), 1.624 (4H, s), 1.407 (4H, s).

EXAMPLE 153-(4-(4-Chlorophenyl)piperidin-1-yl)-2-phenylquinoxaline-6-carboxylicacid

Step 1. Methyl3-(4-(4-chlorophenyl)piperidin-1-yl)-2-phenylquinoxaline-6-carboxylate

Into a 8-mL sealed tube, was placed methyl3-bromo-2-phenylquinoxaline-6-carboxylate (150 mg, 0.44 mmol, 1.00equiv), 4-(4-chlorophenyl)piperidine hydrochloride (204.2 mg, 0.88 mmol,2.00 equiv), DIEA (170.3 mg, 1.32 mmol, 3.00 equiv),N,N-dimethylformamide (4 mL). The resulting solution was stirredovernight at 100° C. in an oil bath. The reaction was then quenched bythe addition of water. The resulting solution was extracted with 6×15 mLof dichloromethane and the organic layers combined and dried overanhydrous sodium sulfate. The solids were filtered out. The resultingmixture was concentrated under vacuum. The residue was applied onto asilica gel column with ethyl acetate/petroleum ether (1:50). Thisresulted in 146.2 mg (71%) of methyl3-(4-(4-chlorophenyl)piperidin-1-yl)-2-phenylquinoxaline-6-carboxylateas a yellow solid.

LC-MS: (ES, m/z): 458 [M+H]+

Step 2.3-(4-(4-Chlorophenyl)piperidin-1-yl)-2-phenylquinoxaline-6-carboxylicacid

Into a 50-mL round-bottom flask, was placed a solution of methyl3-(4-(4-chlorophenyl)piperidin-1-yl)-2-phenylquinoxaline-6-carboxylate(146.2 mg, 0.32 mmol, 1.00 equiv) in MeOH/THF (1:1)(16 mL), a solutionof sodium hydroxide (64 mg, 1.60 mmol, 5.00 equiv) in water (1.5 mL).The resulting solution was stirred overnight at 50° C. in an oil bath.The pH value of the solution was adjusted to 3-4 with 1N hydrogenchloride. The resulting mixture was concentrated under vacuum. Theresulting mixture was washed with methanol. The solid was dissolved inDMF and sent for prep-HPLC to purification. This resulted in 49 mg (35%)of 3-(4-(4-chlorophenyl)piperidin-1-yl)-2-phenylquinoxaline-6-carboxylicacid as a yellow solid.

LC-MS: (ES, m/z): 444 [M+H]+

¹H-NMR (300 MHz, DMSO, ppm): δ 13.264 (1H, s), 8.313 (1H, s),8.046-8.004 (4H, t), 7.586-7.530 (3H, t), 7.377-7.280 (4H, m), 3.902,3.861 (2H, d, J=12.3 Hz), 2.916-2.842 (3H, t), 2.514 (1H, s),1.721-1.644 (4H, t).

EXAMPLE 16 3-Morpholino-2-phenylquinoxaline-6-carboxylic acid

Step 1. Methyl 3-morpholino-2-phenylquinoxaline-6-carboxylate

Into a 8-mL sealed tube, was placed a solution of methyl3-bromo-2-phenylquinoxaline-6-carboxylate (150 mg, 0.44 mmol, 1.00equiv) in N,N-dimethylformamide (4 mL), morpholine (76.6 mg, 0.88 mmol,2.00 equiv), DIEA (170.3 mg, 1.32 mmol, 3.00 equiv). The resultingsolution was stirred overnight at 100° C. in an oil bath. The resultingsolution was concentrated under vacuum. The residue was applied onto asilica gel column with ethyl acetate/petroleum ether (1:10). Thisresulted in 136.4 mg (86%) of methyl3-morpholino-2-phenylquinoxaline-6-carboxylate as a yellow solid.

LC-MS: (ES, m/z): 350 [M+H]⁺

Step 2. 3-Morpholino-2-phenylquinoxaline-6-carboxylic acid

Into a 50-mL round-bottom flask, was placed a solution of methyl3-morpholino-2-phenylquinoxaline-6-carboxylate (136.4 mg, 0.39 mmol,1.00 equiv) in methanol (12 mL), a solution of sodium hydroxide (78.2mg, 1.96 mmol, 5.00 equiv) in water (2 mL). The resulting solution wasstirred overnight at 50° C. in an oil bath. The pH value of the solutionwas adjusted to 3-4 with 1N hydrogen chloride. The resulting mixture wasconcentrated under vacuum. The resulting mixture was sent for prep-HPLC.This resulted in 56 mg (41%) of3-morpholino-2-phenylquinoxaline-6-carboxylic acid as a yellow solid.

LC-MS: (ES, m/z): 336 [M+H]⁺

¹H-NMR (300 MHz, DMSO, ppm): δ 8.323 (s, 1H), 8.026-7.995 (m, 4H),7.609-7.537 (m, 3H), 3.652-3.622 (t, J=9 Hz, 4H), 3.247-3.233 (d, J=4.2Hz, 4H).

EXAMPLE 173-(4-Methyl-1,4-diazepan-1-yl)-2-phenylquinoxaline-6-carboxylic acid

Step 1. Methyl3-(4-methyl-1,4-diazepan-1-yl)-2-phenylquinoxaline-6-carboxylate

Into a 8-mL sealed tube, was placed a solution of methyl3-bromo-2-phenylquinoxaline-6-carboxylate (150 mg, 0.44 mmol, 1.00equiv) in N,N-dimethylformamide (4 mL), 1-methyl-1,4-diazepane (100.3mg, 0.88 mmol, 2.00 equiv), DIEA (170.3 mg, 1.32 mmol, 3.00 equiv). Theresulting solution was stirred overnight at 100° C. in an oil bath. Theresulting solution was concentrated under vacuum. The residue wasapplied onto a silica gel column with dichloromethane/methanol (20:1).This resulted in 126.6 mg (77%) of methyl3-(4-methyl-1,4-diazepan-1-yl)-2-phenylquinoxaline-6-carboxylate asyellow oil.

LC-MS: (ES, m/z): 377 [M+H]⁺

Step 2. 3-(4-Methyl-1,4-diazepan-1-yl)-2-phenylquinoxaline-6-carboxylicacid

Into a 50-mL round-bottom flask, was placed a solution of methyl3-(4-methyl-1,4-diazepan-1-yl)-2-phenylquinoxaline-6-carboxylate (126.6mg, 0.34 mmol, 1.00 equiv) in methanol (12 mL), a solution of sodiumhydroxide (72.6 mg, 1.81 mmol, 5.00 equiv) in water (2.5 mL). Theresulting solution was stirred overnight at 50° C. in an oil bath. ThepH value of the solution was adjusted to 3-4 with 1N hydrogen chloride.The resulting mixture was concentrated under vacuum. The resultingmixture was sent for prop-HPLC. This resulted in 46 mg (38%) of3-(4-methyl-1,4-diazepan-1-yl)-2-phenylquinoxaline-6-carboxylic acid asa yellow solid.

LC-MS: (ES, m/z): 363 [M+H]⁺

¹H NMR (300 MHz, CD₃OD, ppm): δ 8.470-8.465 (d, J=1.5 Hz, 1H),8.102-8.068 (m, 1H), 7.994-7.965 (d, J=8.7 Hz, 1H), 7.807-7.776 (m, 2H),7.588-7.523 (m, 2H), 3.620 (s, 2H), 3.250-3.177 (m, 2H), 2.906 (s, 3H),2.069 (s, 2H), 1.338-1.289 (t, J=14.7 Hz, 4H).

EXAMPLE 18 3-(Isopropylamino)-2-phenylquinoxaline-6-carboxylic acid

Step 1. Methyl 3-(isopropylamino)-2-phenylquinoxaline-6-carboxylate

Into a 8-mL sealed tube, was placed a solution of methyl3-bromo-2-phenylquinoxaline-6-carboxylate (100 mg, 0.29 mmol, 1.00equiv, 99%) in N,N-dimethylformamide (4 mL), propan-2-amine (34.5 mg,0.58 mmol, 2.00 equiv), DIEA (112.23 mg, 0.87 mmol, 3.00 equiv). Theresulting solution was stirred overnight at 100° C. in an oil bath. Theresidue was applied onto a silica gel column with ethylacetate/petroleum ether (1:50). This resulted in 95.6 mg (100%) ofmethyl 3-(isopropylamino)-2-phenylquinoxaline-6-carboxylate as a yellowsolid.

LC-MS: (ES, m/z): 322 [M+H]⁺

Step 2. 3-(Isopropylamino)-2-phenylquinoxaline-6-carboxylic acid

Into a 50-mL round-bottom flask, was placed a solution of methyl3-(isopropylamino)-2-phenylquinoxaline-6-carboxylate (95.6 mg, 0.30mmol, 1.00 equiv) in methanol (19 mL). This was followed by the additionof a solution of sodium hydroxide (60 mg, 1.50 mmol, 5.00 equiv) inwater (3 mL) dropwise with stirring. The resulting solution was stirredovernight at 50° C. in an oil bath. The resulting mixture wasconcentrated under vacuum. The crude product was sent for prep-HPLC toget the product. This resulted in 55 mg (58%) of3-(isopropylamino)-2-phenylquinoxaline-6-carboxylic acid as a yellowsolid.

LC-MS: (ES, m/z): 308 [M+H]⁺

¹H-NMR (300 MHz, CDCl₃, ppm): 8.624 (s, 1H), 8.091-8.057 (m, 2H),7.881-7.550 (m, 3H), 7.678-7.601 (m, 3H), 5.283 (s, 1H), 4.541-4.521 (d,J=6 Hz, 1H), 1.333-1.312 (d, J=6.3 Hz, 6H).

EXAMPLE 192-Phenyl-3-(4-(pyrimidin-2-yl)piperazin-1-yl)quinoxaline-6-carboxylicacid

Step 1. Methyl2-phenyl-3-(4-(pyrimidin-2-yl)piperazin-1-yl)quinoxaline-6-carboxylate

Into a 8-mL sealed tube, was placed methyl3-bromo-2-phenylquinoxaline-6-carboxylate (150 mg, 0.44 mmol, 1.00equiv), 2-(piperazin-1-yl)pyrimidine (144.3 mg, 0.88 mmol, 2.00 equiv),DIEA (170.3 mg, 1.32 mmol, 3.00 equiv), N,N-dimethylformamide (3 mL).The resulting solution was stirred overnight at 100° C. in an oil bath.The resulting solution was concentrated under vacuum. The residue wasapplied onto a silica gel column with ethyl acetate/petroleum ether(1:50). This resulted in 192 mg (95%) of methyl2-phenyl-3-(4-(pyrimidin-2-yl)piperazin-1-yl)quinoxaline-6-carboxylateas a yellow solid.

LC-MS: (ES, m/z): 427 [M+H]⁺

Step 2.2-Phenyl-3-(4-(pyrimidin-2-yl)piperazin-1-yl)quinoxaline-6-carboxylicacid

Into a 50-mL round-bottom flask, was placed a solution of methyl2-phenyl-3-(4-(pyrimidin-2-yl)piperazin-1-yl)quinoxaline-6-carboxylate(192 mg, 0.41 mmol, 1.00 equiv, 90%) in methanol (10 mL), a solution ofsodium hydroxide (80 mg, 2.00 mmol, 5.00 equiv) in water (2 mL). Theresulting solution was stirred overnight at 50° C. in an oil bath. Theresulting mixture was concentrated under vacuum. The resulting mixturewas washed with methanol. This resulted in 80 mg (47%) of2-phenyl-3-(4-(pyrimidin-2-yl)piperazin-1-yl)quinoxaline-6-carboxylicacid as a yellow solid.

LC-MS: (ES, m/z): 413 [M+H]⁺

¹H-NMR (300 MHz, DMSO, ppm): δ 13.275 (s, 1H), 8.389-8.336 (t, 3H),8.062-8.026 (t, 4H), 7.609-7.571 (t, 3H), 6.685-6.654 (t, 1H), 3.774 (s,4H).

EXAMPLE 202-Phenyl-3-(4-(5-(trifluoromethyl)pyridin-2-yl)piperazin-1-yl)quinoxaline-6-carboxylic acid

Step 1. Methyl2-phenyl-3-(4-(5-(trifluoromethyl)pyridin-2-yl)piperazin-1-yl)quinoxaline-6-carboxylate

Into a 8-mL sealed tube, was placed methyl3-bromo-2-phenylquinoxaline-6-carboxylate (150 mg, 0.44 mmol, 1.00equiv), 1-(5-(trifluoromethyl)pyridin-2-yl)piperazine (203.28 mg, 0.88mmol, 2.00 equiv), DIEA (170.3 mg, 1.32 mmol, 3.00 equiv),N,N-dimethylformamide (3 mL). The resulting solution was stirredovernight at 100° C. in an oil bath. The reaction was then quenched bythe addition of water. The resulting solution was extracted with 4×30 mLof dichloromethane and the organic layers combined and dried overanhydrous sodium sulfate. The solids were filtered out. The residue wasapplied onto a silica gel column with ethyl acetate/petroleum ether(1:50). This resulted in 210.8 mg (97%) of methyl2-phenyl-3-(4-(5-(trifluoromethyl)pyridin-2-yl)piperazin-1-yl)quinoxaline-6-carboxylateas a yellow solid.

LC-MS: (ES, m/z): 494 [M+H]⁺

Step 2.2-Phenyl-3-(4-(5-(trifluoromethyl)pyridin-2-yl)piperazin-1-yl)quinoxaline-6-carboxylicacid

Into a 50-mL round-bottom flask, was placed a solution of methyl2-phenyl-3-(4-(5-(trifluoromethyl)pyridin-2-yl)piperazin-1-yl)quinoxaline-6-carboxylate(210.8 mg, 0.43 mmol, 1.00 equiv) in methanol (15 mL). This was followedby the addition of a solution of sodium hydroxide (85.5 mg, 2.14 mmol,5.00 equiv) in water (1.5 mL), which was added dropwise with stirring.The sulting solution was stirred overnight at 50° C. in an oil bath. ThepH value of the solution was adjusted to 3-4 with 1N hydrochloric acid.The mixture was concentrated under vacuum. The resulting mixture waswashed with methanol. This resulted in 78 mg (38%) of2-phenyl-3-(4-(5-(trifluoromethyl)pyridin-2-yl)piperazin-1-yl)quinoxaline-6-carboxylicacid as a yellow solid.

LC-MS: (ES, m/z): 480 [M+H]⁺

¹H-NMR (300 MHz, DMSO, ppm): δ 13.310 (s, 1H), 8.425-8.337 (d, J=26.4Hz, 2H), 8.026 (s, 4H), 7.829-7.800 (d, J=8.7 Hz, 1H), 7.589-7.570 (d,J=5.7 Hz, 3H) 6.993-6.963 (d, J=9 Hz, 1H), 3.694 (s, 4H), 3.372 (s, 4H).

EXAMPLE 212-phenyl-3-(4-(quinolin-2-yl)piperazin-1-yl)quinoxaline-6-carboxylicacid

Step 1. Methyl2-phenyl-3-(4-(quinolin-2-yl)piperazin-1-yl)quinoxaline-6-carboxylate

Into a 8-mL sealed tube, was placed methyl3-bromo-2-phenylquinoxaline-6-carboxylate (150 mg, 0.44 mmol, 1.00equiv), 3-(piperazin-1-yl)isoquinoline dihydrochloride (250.8 mg, 0.88mmol, 2.00 equiv), DIEA (170.3 mg, 1.32 mmol, 3.00 equiv),N,N-dimethylformamide (3 mL). The resulting solution was stirredovernight at 100° C. in an oil bath. The reaction was then quenched bythe addition of water. The resulting solution was extracted with 4×30 mLof dichloromethane and the organic layers combined and dried overanhydrous sodium sulfate. The solids were filtered out. The mixture wasconcentrated under vacuum. The residue was applied onto a silica gelcolumn with ethyl acetate/petroleum ether (1:10). This resulted in 216.6mg (crude) of methyl3-(4-(isoquinolin-3-yl)piperazin-1-yl)-2-phenylquinoxaline-6-carboxylateas a yellow solid.

LC-MS (ES, m/z): 476 [M+H]⁺

Step 2.3-(4-(Isoquinolin-3-yl)piperazin-1-yl)-2-phenylquinoxaline-6-carboxylicacid

Into a 50-mL round-bottom flask, was placed a solution of methyl3-(4-(isoquinolin-3-yl)piperazin-1-yl)-2-phenylquinoxaline-6-carboxylate(216.6 mg, 0.46 mmol, 1.00 equiv) in methanol (15 mL). This was followedby the addition of a solution of sodium hydroxide (91.2 mg, 2.28 mmol,5.00 equiv) in water (2 mL), which was added dropwise with stirring. Theresulting solution was stirred overnight at 50° C. in an oil bath. ThepH value of the solution was adjusted to 3-4 with 1N hydrochloric acid.The resulting mixture was concentrated under vacuum. The resultingmixture was washed with methanol. This resulted in 56 mg (26%) of3-(4-(isoquinolin-3-yl)piperazin-1-yl)-2-phenylquinoxaline-6-carboxylicacid as a yellow solid.

LC-MS: (ES, m/z): 462 [M+H]⁺

¹H-NMR (300 MHz, DMSO, ppm): 13.290 (s, 1H), 8.351 (s, 1H), 8.073-8.031(m, 5H), 7.729-7.703 (d, J=7.8 Hz, 1H), 7.603-7.513 (m, 5H), 7.284-7.223(m, 2H), 3.755 (s, 4H), 3.411 (s, 4H).

EXAMPLE 22 2-(Azepan-1-yl)-3-phenylquinoxaline-6-carboxylic acid

Step 1. Methyl 2-(azepan-1-yl)-3-phenylquinoxaline-6-carboxylate

Into a 8-mL sealed tube, was placed a solution of methyl2-bromo-3-phenylquinoxaline-6-carboxylate (150 mg, 0.44 mmol, 1.00equiv) in N,N-dimethylformamide (4 mL), HMI (87.27 mg, 0.88 mmol, 2.00equiv), DIEA (170.3 mg, 1.32 mmol, 3.00 equiv). The resulting solutionwas stirred overnight at 100° C. in an oil bath. The residue was appliedonto a silica gel column with ethyl acetate/petroleum ether (1:50). Thisresulted in 136 mg (84%) of methyl2-(azepan-1-yl)-3-phenylquinoxaline-6-carboxylate as a yellow solid.

LC-MS: (ES, m/z): 362 [M+H]⁺

Step 2. 2-(Azepan-1-yl)-3-phenylquinoxaline-6-carboxylic acid

Into a 50-mL round-bottom flask, was placed a solution of methyl2-(azepan-1-yl)-3-phenylquinoxaline-6-carboxylate (136 mg, 0.37 mmol,1.00 equiv, 98%) in methanol (10 mL), sodium hydroxide (75.3 mg, 1.88mmol, 5.00 equiv). The resulting solution was stirred overnight at 50°C. in an oil bath. The pH value of the solution was adjusted to 3-4 with1N hydrogen chloride. The resulting mixture was concentrated undervacuum. The resulting mixture was washed with methanol. This resulted in63.1 mg (47%) of 2-(azepan-1-yl)-3-phenylquinoxaline-6-carboxylic acidas a yellow solid.

LC-MS: (ES, m/z): 348 [M+H]⁺

¹H-NMR (300 MHz, DMSO, ppm): 12.992 (s, 1H), 8.376-8.371 (d, J=1.5 Hz,1H), 8.093-8.058 (m, 1H), 7.723-7.694 (t, J=8.7 Hz, 3H), 7.556-7.487 (m,3H), 3.467-3.428 (t, J=12.7 Hz, 4H), 1.621 (s, 4H), 1.404 (s, 4H).

EXAMPLE 23 3-Phenyl-2-(piperidin-1-yl)quinoxaline-6-carboxylic acid

Step 1. Synthesis of methyl3-phenyl-2-(piperidin-1-yl)quinoxaline-6-carboxylate

Into a 8-mL sealed tube, was placed a solution of methyl2-bromo-3-phenylquinoxaline-6-carboxylate (150 mg, 0.44 mmol, 1.00equiv) in N,N-dimethylformamide (4 mL), piperidine (74.8 mg, 0.88 mmol,2.00 equiv), DIEA (170.3 mg, 1.32 mmol, 3.00 equiv). The resultingsolution was stirred overnight at 100° C. in an oil bath. The residuewas applied onto a silica gel column with ethyl acetate/petroleum ether(1:10). This resulted in 170.9 mg (crude) of methyl3-phenyl-2-(piperidin-1-yl)quinoxaline-6-carboxylate as a yellow solid.

LC-MS: (ES, m/z): 348 [M+H]⁺

Step 2. 3-Phenyl-2-(piperidin-1-yl)quinoxaline-6-carboxylic acid

Into a 50-mL round-bottom flask, was placed a solution of methyl3-phenyl-2-(piperidin-1-yl)quinoxaline-6-carboxylate (170.9 mg, 0.49mmol, 1.00 equiv) in methanol (12 mL), sodium hydroxide (98.5 mg, 2.46mmol, 5.00 equiv). The resulting solution was stirred overnight at 50°C. in an oil bath. The pH value of the solution was adjusted to 3-4 with1N hydrogen chloride. The resulting mixture was concentrated undervacuum. The resulting mixture was washed with methanol. This resulted in86 mg (52%) of 3-phenyl-2-(piperidin-1-yl)quinoxaline-6-carboxylic acidas a yellow solid.

LC-MS: (ES, m/z): 334 [M+H]⁺

¹H-NMR (300 MHz, DMSO, ppm): 13.034 (s, 1H), 8.419-8.414 (d, J=1.5 Hz,1H), 8.131-8.096 (m, 1H), 7.955-7.934 (s, J=6.3 Hz, 1H), 7.796-7.767 (s,J=8.7 Hz, 1H), 7.585-7.490 (m, 3H), 1.530 (s, 6H).

EXAMPLE 24 2-(4-(4-Chlorophenyl)piperidin-1-yl)-3-(4-fluorophenyl)quinoxaline-6-carboxylic acid

Step 1. Methyl2-(4-(4-chlorophenyl)piperidin-1-yl)-3-(4-fluorophenyl)quinoxaline-6-carboxylate

Into a 10-mL sealed tube, was placed a solution of methyl2-chloro-3-(4-fluorophenyl)quinoxaline-6-carboxylate (150 mg, 0.47 mmol,1.00 equiv) in N,N-dimethylformamide (5 mL),4-(4-chlorophenyl)piperidine hydrochloride (219 mg, 0.94 mmol, 2.00equiv), potassium carbonate (326 mg, 2.36 mmol, 5.00 equiv). Theresulting solution was stirred overnight at 100° C. in an oil bath. Thereaction was then quenched by the addition of 20 mL of water. Theresulting solution was extracted with dichloromethane/methanol (10:1)and the organic layers were combined. The resulting mixture wasconcentrated under vacuum. The residue was applied onto a silica gelcolumn with ethyl acetate/petroleum ether (1:10). This resulted in 200mg (89%) of methyl2-(4-(4-chlorophenyl)piperidin-1-yl)-3-(4-fluorophenyl)quinoxaline-6-carboxylateas a yellow solid.

LC-MS: (ES, m/z): 476 [M+H]⁺

Step 2.2-(4-(4-Chlorophenyl)piperidin-1-yl)-3-(4-fluorophenyl)quinoxaline-6-carboxylicacid

Into a 100-mL round-bottom flask, was placed a solution of methyl2-(4-(4-chlorophenyl)piperidin-1-yl)-3-(4-fluorophenyl)quinoxaline-6-carboxylate(200 mg, 0.42 mmol, 1.00 equiv) in methanol (30 mL), sodium hydroxide(84 mg, 2.10 mmol, 5.00 equiv). The resulting solution was stirred for130 minutes at 50° C. in an oil bath. The resulting mixture wasconcentrated under vacuum. The resulting solution was diluted with 30 mLof water. The pH value of the solution was adjusted to 3 with 1Nhydrochloric acid. The solids were collected by filtration. The solidwas dried in an oven under reduced pressure. This resulted in 110 mg(57%) of2-(4-(4-chlorophenyl)piperidin-1-yl)-3-(4-fluorophenyl)quinoxaline-6-carboxylicacid as a yellow solid.

LC-MS: (ES, m/z): 462 [M+H]⁺

¹H-NMR (300 MHz, DMSO, ppm): 13.119 (s, 1H), 8.430 (s, 1H), 8.142-8.051(m, 3H), 7.821-7.793 (d, J=8.4 Hz, 1H), 7.437-7.281 (m, 6H), 3.923-3.88(m, 2H), 2.934-2.742 (m, 3H), 1.732-1.645 (m, 4H).

EXAMPLE 252-(4-(3-Chlorophenyl)piperidin-1-yl)-3-(4-fluorophenyl)quinoxaline-6-carboxylicacid

Step 1. Methyl 2-(4-(3-chlorophenyl)piperidin-1-yl)-3-(4-fluorophenyl)quinoxaline-6-carboxylate

Into a 8-mL sealed tube, was placed methyl2-chloro-3-(4-fluorophenyl)quinoxaline-6-carboxylate (200 mg, 0.63 mmol,1.00 equiv), 4-(3-chlorophenyl)piperidine hydrochloride (292.4 mg, 1.27mmol, 2.00 equiv), potassium carbonate (436.7 mg, 3.16 mmol, 5.00equiv), N,N-dimethylformamide (4 mL). The resulting solution was stirredovernight at 100° C. in an oil bath. The residue was applied onto asilica gel column with ethyl acetate/petroleum ether (1:10). Thisresulted in 137 mg (43%) of methyl2-(4-(3-chlorophenyl)piperidin-1-yl)-3-(4-fluorophenyl)quinoxaline-6-carboxylateas a yellow solid.

LC-MS: (ES, m/z): 476 [M+H]⁺

Step 2.2-(4-(3-Chlorophenyl)piperidin-1-yl)-3-(4-fluorophenyl)quinoxaline-6-carboxylicacid

Into a 50-mL round-bottom flask, was placed a solution of methyl2-(4-(3-chlorophenyl)piperidin-1-yl)-3-(4-fluorophenyl)quinoxaline-6-carboxylate(137.2 mg, 0.28 mmol, 1.00 equiv, 98%) in methanol (20 mL). This wasfollowed by the addition of a solution of sodium hydroxide (57.8 mg,1.45 mmol, 5.00 equiv) in water (2 mL), which was added dropwise withstirring. The resulting solution was stirred for overnight at 50° C. inan oil bath. The pH value of the solution was adjusted to 3-4 with 1Nhydrochloric acid. The resulting mixture was concentrated under vacuum.The resulting mixture was washed with methanol. This resulted in 43 mg(33%) of2-(4-(3-chlorophenyl)piperidin-1-yl)-3-(4-fluorophenyl)quinoxaline-6-carboxylicacid as a yellow solid.

LC-MS: (ES, m/z): 462 [M+H]⁺

¹H-NMR (300 MHz, CDCl₃, ppm): 8.432 (s, 1H), 8.428-8.055 (m, 3H),7.808-7.779 (d, J=8.7 Hz, 1H), 7.439-7.230 (m, 6H), 3.914-3.871 (d,J=12.9 Hz, 2H), 2.918-2.844 (m, 2H), 2.791-2.716 (t, J=22.5 Hz, 1H),1.751-1.631 (m, 4H).

EXAMPLE 263-(4-Fluorophenyl)-2-(4-(4-methoxyphenyl)piperidin-1-yl)quinoxaline-6-carboxylicacid

Step 1. Methyl3-(4-fluorophenyl)-2-(4-(4-methoxyphenyl)piperidin-1-yl)quinoxaline-6-carboxylate

Into a 8-mL sealed tube, was placed methyl2-chloro-3-(4-fluorophenyl)quinoxaline-6-carboxylate (200 mg, 0.63 mmol,1.00 equiv), 4-(4-methoxyphenyl)piperidine (138 mg, 0.72 mmol, 2.00equiv), potassium carbonate (436.7 mg, 3.16 mmol, 5.00 equiv),N,N-dimethylformamide (4 mL). The resulting solution was stirredovernight at 100° C. in an oil bath. The residue was applied onto asilica gel column with ethyl acetate/petroleum ether (1:10). Thisresulted in 123.9 mg (37%) of methyl3-(4-fluorophenyl)-2-(4-(4-methoxyphenyl)piperidin-1-yl)quinoxaline-6-carboxylateas a yellow solid.

LC-MS: (ES, m/z): 472 [M+H]⁺

Step 2.3-(4-Fluorophenyl)-2-(4-(4-methoxyphenyl)piperidin-1-yl)quinoxaline-6-carboxylicacid

Into a 50-mL round-bottom flask, was placed a solution of methyl3-(4-fluorophenyl)-2-(4-(4-methoxyphenyl)piperidin-1-yl)quinoxaline-6-carboxylate(123.9 mg, 0.24 mmol, 1.00 equiv, 93%) in methanol (15 mL). This wasfollowed by the addition of a solution of sodium hydroxide (52.6 mg,1.31 mmol, 5.00 equiv) in water (3 mL), which was added dropwise withstirring. The resulting solution was stirred for overnight at 50° C. inan oil bath. The pH value of the solution was adjusted to 3-4 with 1Nhydrochloric acid. The resulting mixture was concentrated under vacuum.The resulting mixture was washed with methanol. This resulted in 60 mg(52%) of3-(4-fluorophenyl)-2-(4-(4-methoxyphenyl)piperidin-1-yl)quinoxaline-6-carboxylicacid as a yellow solid.

LC-MS: (ES, m/z): 458 [M+H]⁺

¹H-NMR (300 MHz, CDCl₃, ppm): 8.794-8.789 (d, J=1.5 Hz, 1H), 8.309-8.274(m, 1H), 8.085-8.038 (m, 2H), 7.900-7.871 (d, J=8.7 Hz, 1H), 7.273-7.155(m, 4H), 6.905-6.877 (d, J=8.4 Hz, 2H), 4.079-4.035 (d, J=13.2 Hz, 2H),2.988-2.909 (t, J=23.7 Hz, 2H), 2.733-2.656 (t, J=23.1 Hz, 1H),1.899-1.684 (m, 4H).

EXAMPLE 273-(4-Fluorophenyl)-2-(4-(pyridin-2-yl)piperazin-1-yl)quinoxaline-6-carboxylicacid

Step 1. Methyl3-(4-fluorophenyl)-2-(4-(pyridin-2-yl)piperazin-1-yl)quinoxaline-6-carboxylate

Into a 8-mL sealed tube, was placed methyl2-chloro-3-(4-fluorophenyl)quinoxaline-6-carboxylate (200 mg, 0.63 mmol,1.00 equiv), 1-(pyridin-2-yl)piperazine (207 mg, 1.27 mmol, 2.00 equiv),potassium carbonate (436.7 mg, 3.16 mmol, 5.00 equiv),N,N-dimethylformamide (4 mL). The resulting solution was stirredovernight at 100° C. in an oil bath. The reaction was then quenched bythe addition of water. The resulting solution was extracted with 5×50 mLof dichloromethane and the organic layers combined. The mixture wasconcentrated under vacuum. The residue was applied onto a silica gelcolumn with ethyl acetate/petroleum ether (1:50). This resulted in 157.4mg (56%) of methyl3-(4-fluorophenyl)-2-(4-(pyridin-2-yl)piperazin-1-yl)quinoxaline-6-carboxylateas a yellow solid.

LC-MS: (ES, m/z): 444 [M+H]⁺

Step 2.3-(4-Fluorophenyl)-2-(4-(pyridin-2-yl)piperazin-1-yl)quinoxaline-6-carboxylicacid

Into a 50-mL round-bottom flask, was placed a solution of methyl3-(4-fluorophenyl)-2-(4-(pyridin-2-yl)piperazin-1-yl)quinoxaline-6-carboxylate(157.4 mg, 0.36 mmol, 1.00 equiv) in methanol (15 mL). This was followedby the addition of a solution of sodium hydroxide (71.1 mg, 1.78 mmol,5.00 equiv) in water (2 mL) dropwise with stirring. The resultingsolution was stirred overnight at 50° C. in an oil bath. The pH value ofthe solution was adjusted to 3-4 with 1N hydrochloric acid. Theresulting mixture was concentrated under vacuum. The resulting mixturewas washed with methanol. This resulted in 36 mg (23%) of3-(4-fluorophenyl)-2-(4-(pyridin-2-yl)piperazin-1-yl)quinoxaline-6-carboxylicacid as a yellow solid.

LC-MS: (ES, m/z): 430 [M+H]⁺

¹H-NMR (300 MHz, DMSO, ppm): δ 8.468-8.463 (d, J=1.5 Hz, 1H),8.180-8.146 (m, 3H), 8.099-8.053 (t, 1H), 7.874-7.794 (t, 1H),7.448-7.389 (t, 2H), 7.140 (s, 1H), 6.833 (s, 1H), 3.670 (s, 4H), 3.452(s, 4H).

EXAMPLE 282-Phenyl-3-(4-(3-(trifluoromethyl)pyridin-2-yl)piperazin-1-yl)quinoxaline-6-carboxylic acid

Step 1. tert-Butyl4-(3-(trifluoromethyl)pyridin-2-yl)-5,6-dihydropyridine-1(2H)-carboxylate

Into a 20 mL sealed tube was placed 2-chloro-3-(trifluoromethyl)pyridine(500 mg, 2.76 mmol, 1.00 equiv), tert-butyl4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-5,6-dihydropyridine-1(2H)-carboxylate(1.705 g, 5.52 mmol, 2.00 equiv), PCy₃ (216.4 mg, 0.77 mmol, 0.28equiv), Pd₂(dba)₃ (304.7 mg, 0.33 mmol, 0.12 equiv), NaOt-Bu (828 mg,8.28 mmol, 3.00 equiv), dioxane (8 mL). The resulting solution wasstirred overnight at 100° C. in an oil bath. The resulting mixture wasconcentrated under vacuum. The residue was applied onto a silica gelcolumn with PE/EA (10:1). This resulted in 449.3 mg (46%) of tert-butyl4-(3-(trifluoromethyl)pyridin-2-yl)-5,6-dihydropyridine-1(2H)-carboxylateas yellow oil.

LC-MS: (ES, m/z): 329[M+H]⁺

Step 2. tert-Butyl4-(3-(trifluoromethyl)pyridin-2-yl)piperidine-1-carboxylate

Into a 50-mL round-bottom flask was purged and maintained with an inertatmosphere of hydrogen, was added a solution of tert-butyl4-(3-(trifluoromethyl)pyridin-2-yl)-5,6-dihydropyridine-1(2H)-carboxylate(449.3 mg, 1.27 mmol, 1.00 equiv, 93%) in methanol (20 mL) and Palladiumcarbon anhydrous (134.8 mg). The resulting solution was stirredovernight at room temperature. The solids were filtered out. Theresulting mixture was concentrated under vacuum. This resulted in 379.8mg (87%) of tert-butyl4-(3-(trifluoromethyl)pyridin-2-yl)piperidine-1-carboxylate as colorlessoil.

LC-MS: (ES, m/z): 331 [M+H]⁺

Step 3. 2-(Piperidin-4-yl)-3-(trifluoromethyl)pyridine

Into a 50-mL round-bottom flask, was placed a solution of tert-butyl4-(3-(trifluoromethyl)pyridin-2-yl)piperidine-1-carboxylate (379.8 mg,1.10 mmol, 1.00 equiv, 96%) in dichloromethane (10 mL). This wasfollowed by the addition of trifluoroacetic acid (5 mL) dropwise withstirring at 0° C. The resulting solution was stirred for 3 h at roomtemperature. The pH value of the solution was adjusted to 8-9 with satsodium bicarbonate. The resulting solution was extracted with 6×50 mL ofdichloromethane and the organic layers combined and dried over anhydroussodium sulfate. The solids were filtered out. The resulting mixture wasconcentrated under vacuum. This resulted in 237.4 mg (93%) of2-(piperidin-4-yl)-3-(trifluoromethyl)pyridine as yellow oil.

LC-MS: (ES, m/z): 231 [M+H]⁺

Step 4. Methyl2-phenyl-3-(4-(3-(trifluoromethyl)pyridin-2-yl)piperidin-1-yl)quinoxaline-6-carboxylate

Into a 8-mL sealed tube, was placed methyl3-bromo-2-phenylquinoxaline-6-carboxylate (176.5 mg, 0.52 mmol, 1.00equiv), 2-(piperidin-4-yl)-3-(trifluoromethyl)pyridine (237.4 mg, 1.03mmol, 2.00 equiv), potassium carbonate (356.1 mg, 2.58 mmol, 5.00 equiv)and N,N-dimethylformamide (4 mL). The resulting solution was stirredovernight at 100° C. in an oil bath. The residue was applied onto asilica gel column with ethyl acetate/petroleum ether (1:50). Thisresulted in 236.2 mg (87%) of methyl2-phenyl-3-(4-(3-(trifluoromethyl)pyridin-2-yl)piperidin-1-yl)quinoxaline-6-carboxylateas a yellow solid.

LC-MS: (ES, m/z): 493 [M+H]⁺

Step 5.2-Phenyl-3-(4-(3-(trifluoromethyl)pyridin-2-yl)piperidin-1-ylquinoxaline-6-carboxylicacid

Into a 50-mL round-bottom flask, was placed a solution of methyl2-phenyl-3-(4-(3-(trifluoromethyl)pyridin-2-yl)piperidin-1-yl)quinoxaline-6-carboxylate (236.2 mg, 0.46mmol, 1.00 equiv, 95%) in methanol (15 mL). This was followed by theaddition of a solution of sodium hydroxide (91.2 mg, 5.00 equiv) inwater (2 mL), which was added dropwise with stirring. The resultingsolution was stirred overnight at 50° C. in an oil bath. The pH value ofthe solution was adjusted to 3-4 with 1N hydrochloric acid. Theresulting mixture was concentrated under vacuum. The resulting mixturewas washed with methanol. This resulted in 105.4 mg (48%) of2-phenyl-3-(4-(3-(trifluoromethyl)pyridin-2-yl)piperidin-1-yl)quinoxaline-6-carboxylicacid as a yellow solid.

LC-MS: (ES, m/z): 479 [M+H]⁺

¹H-NMR (300 MHz, DMSO, ppm): 13.201 (s, 1H), 8.848-8.834 (d, J=4.2 Hz,1H), 8.316 (s, 1H), 8.135-8.111 (d, J=7.2 Hz, 1H), 8.028-8.010 (d, J=5.4Hz, 4H), 7.605-7.455 (m, 4H), 3.947-3.904 (d, J=12.9 Hz, 2H),3.186-3.147 (m, 1H), 2.946-3.881 (t, J=12.3 Hz, 2H), 2.083-1.966 (dd,J=12.6 Hz, 2H), 1.668-1.631 (d, J=11.1 Hz, 2H).

EXAMPLE 293-(4-Fluorophenyl)-2-(4-(4-(trifluoromethyl)phenyl)piperidin-1-yl)quinoxaline-6-carboxylicacid

Step 1. Methyl3-(4-fluorophenyl)-2-(4-(4-(trifluoromethyl)phenyl)piperidin-1-yl)quinoxaline-6-carboxylate

Into a 20-mL sealed tube, was placed a solution of4-(4-(trifluoromethyl)phenyl)piperidine (420 mg, 1.83 mmol, 3.00 equiv),methyl 2-chloro-3-(4-fluorophenyl)quinoxaline-6-carboxylate (150 mg,0.47 mmol, 1.00 equiv), DIEA (305 mg, 2.36 mmol, 5.00 equiv) inN,N-dimethylformamide (10 mL). The resulting solution was stirredovernight at 100° C. in an oil bath. The resulting mixture wasconcentrated under vacuum. The residue was applied onto a silica gelcolumn with ethyl acetate/petroleum ether (1:10). This resulted in 200mg (83%) of methyl3-(4-fluorophenyl)-2-(4-(4-(trifluoromethyl)phenyl)piperidin-1-yl)quinoxaline-6-carboxylateas a yellow solid.

LC-MS: (ES, m/z): 510 [M+H]⁺

Step 2.3-(4-Fluorophenyl)-2-(4-(4-(trifluoromethyl)phenyl)piperidin-1-yl)quinoxaline-6-carboxylicacid

Into a 50-mL round-bottom flask, was placed a solution of methyl3-(4-fluorophenyl)-2-(4-(4-(trifluoromethyl)phenyl)piperidin-1-yl)quinoxaline-6-carboxylate(120 mg, 0.24 mmol, 1.00 equiv) in methanol (20 mL) and a solution ofsodium hydroxide (47.2 mg, 1.18 mmol, 5.00 equiv) in water (2 mL). Theresulting solution was stirred for 3 h at 50° C. in an oil bath. Theresulting mixture was concentrated under vacuum. The resulting solutionwas diluted with 30 mL of water. The pH value of the aqueous solutionwas adjusted to 3 with 1N hydrochloric acid. The resulting solids werecollected by filtration and washed with 10 mL×1 of water. The solid wasdried in an oven under reduced pressure. The solid was purified byre-crystallization from methanol. This resulted in 60 mg (51%) of3-(4-fluorophenyl)-2-(4-(4-(trifluoromethyl)phenyl)piperidin-1-yl)quinoxaline-6-carboxylicacid as a yellow solid.

LC-MS: (ES, m/z): 496 [M+H]⁺

¹H-NMR (300 MHz, DMSO, ppm): 13.105 (s, 1H), 8.447 (s, 1H), 8.158-8.072(m, 3H), 7.841-7.812 (m, 1H), 7.608-7.558 (m, 4H), 7.449-7.391 (m, 2H),3.962-3.920 (m, 2H), 2.971-2.888 (m, 3H), 1.800-1.723 (m, 4H).

EXAMPLE 30 2,3-Bis(4-phenylpiperidin-1-yl)quinoxaline-6-carboxylic acid

Step 1. Ethyl 2,3-dioxo-1,2,3,4-tetrahydroquinoxaline-6-carboxylate

Into a 250-mL round-bottom flask, was placed a solution of ethyl3,4-diaminobenzoate (5 g, 27.75 mmol, 1.00 equiv) in diethyl oxalate(100 mL). The resulting solution was stirred overnight at 140° C. in anoil bath. Then the resulting solution was cooled to room temperature.The solids were collected by filtration. The solid was dried in an ovenunder reduced pressure. This resulted in 3.5 g (54%) of ethyl2,3-dioxo-1,2,3,4-tetrahydroquinoxaline-6-carboxylate as a brown solid.

Step 2. Ethyl 2,3-dichloroquinoxaline-6-carboxylate

Into a 250-mL round-bottom flask, was placed a solution of ethyl2,3-dioxo-1,2,3,4-tetrahydroquinoxaline-6-carboxylate (3.7 g, 15.80mmol, 1.00 equiv) in toluene (100 mL), thionyl chloride (37.6 g, 315.97mmol, 20.00 equiv), N,N-dimethylformamide (2.75 g, 31.61 mmol, 2.00equiv). The resulting solution was heated to reflux for 3 h in an oilbath. The resulting mixture was concentrated under vacuum. The resultingmixture was washed with 100 mL of ether. This resulted in 2.5 g (58%) ofethyl 2,3-dichloroquinoxaline-6-carboxylate as a brown solid.

LC-MS: (ES, m/z): 271 [M+H]⁺

Step 3. Ethyl 2,3-bis(4-phenylpiperidin-1-yl)quinoxaline-6-carboxylate

Into a 20-mL sealed tube, was placed a solution of ethyl2,3-dichloroquinoxaline-6-carboxylate (150 mg, 0.55 mmol, 1.00 equiv),4-phenylpiperidine (298 mg, 1.85 mmol, 3.00 equiv), DIEA (398 mg, 3.09mmol, 5.00 equiv) in N,N-dimethylformamide (10 mL). The resultingsolution was stirred overnight at 100° C. in an oil bath. The resultingmixture was concentrated under vacuum. The residue was applied onto asilica gel column with ethyl acetate/petroleum ether (1:10). Thisresulted in 180 mg (62%) of ethyl2,3-bis(4-phenylpiperidin-1-yl)quinoxaline-6-carboxylate as a yellowsolid.

LC-MS: (ES, m/z): 521 [M+H]⁺

Step 4. 2,3-Bis(4-phenylpiperidin-1-yl)quinoxaline-6-carboxylic acid

Into a 50-mL round-bottom flask, was placed a solution of ethyl2,3-bis(4-phenylpiperidin-1-yl)quinoxaline-6-carboxylate (150 mg, 0.29mmol, 1.00 equiv) in methanol (25 mL) and a solution of sodium hydroxide(58 mg, 1.45 mmol, 5.00 equiv) in water (2 mL). The resulting solutionwas stirred for 3 h at 50° C. in an oil bath. The resulting mixture wasconcentrated under vacuum. The resulting solution was diluted with 30 mLof water. The pH value of the aqueous solution was adjusted to 3 with 1Nhydrochloric acid. The resulting solids were collected by filtration.The solid was dried in an oven under reduced pressure and purified byre-crystallization from methanol. This resulted in 80 mg (56%) of2,3-bis(4-phenylpiperidin-1-yl)quinoxaline-6-carboxylic acid as a yellowsolid.

LC-MS: (ES, m/z): 493 [M+H]⁺

¹H-NMR (300 MHz, DMSO, ppm): 12.952 (s, 1H), 8.172 (s, 1H), 7.915-7.883(d, J=9.6 Hz, 1H), 7.662-7.634 (d, J=8.4 Hz, 1H), 7.292-7.197 (m, 10H),4.605-4.426 (m, 4H), 3.072-2.831 (m, 6H), 1.830-1.791 (m, 8H).

EXAMPLE 31 2,3-Bis(4-methoxyphenyl)-6-(1H-tetrazol-5-yl) quinoxaline

Step 1. 2,3-Bis(4-methoxyphenyl)quinoxaline-6-carbonitrile

Into a 100-mL round-bottom flask, was placed a solution of1,2-bis(4-methoxyphenyl)ethane-1,2-dione (200 mg, 0.74 mmol, 1.00 equiv)in acetic acid (20 mL), 3,4-diaminobenzonitrile (118.2 mg, 0.89 mmol,1.20 equiv). The resulting solution was stirred for 1 h at reflux in anoil bath. The reaction was then quenched by the addition of water. Thesolids were collected by filtration and washed with MeOH. This resultedin 205 mg (71%) of 2,3-bis(4-methoxyphenyl)quinoxaline-6-carbonitrile asa yellow solid.

LC-MS-PH: (ES, m/z): 368 [M+H]⁺

Step 2. 2,3-Bis(4-methoxyphenyl)-6-(1H-tetrazol-5-yl)quinoxaline

Into a 20-mL sealed tube, was placed a solution of2,3-bis(4-methoxyphenyl)quinoxaline-6-carbonitrile (200 mg, 0.51 mmol,1.00 equiv, 93%) in N,N-dimethylformamide (7 mL), NaN3 (500 mg, 7.69mmol, 15.18 equiv), NH4Cl (147.9 mg, 2.79 mmol, 5.00 equiv). Theresulting solution was stirred for 4 h at 100° C. in an oil bath. Thereaction was then quenched by the addition of water. The resultingsolution was extracted with 8×50 mL of dichloromethane/MeOH (10:1) andthe organic layers combined and dried over anhydrous sodium sulfate. Thesolids were filtered out. The resulting mixture was concentrated undervacuum. The resulting mixture was washed with methanol. This resulted in47 mg (23%) of 2,3-bis(4-methoxyphenyl)-6-(1H-tetrazol-5-yl)quinoxalineas a yellow solid.

LC-MS: (ES, m/z): 411 [M+H]+

¹H-NMR (300 MHz, DMSO, ppm): δ 8.760 (1H, s), 8.463-8.293 (4H, m),7.523, 7.498 (4H, d, J=7.5 Hz), 6.995, 6.971 (4H, d, J=7.2 Hz), 3.861(6H, s).

EXAMPLE 323-(4-(N-Methylmethan-3-ylsulfonamido)piperidin-1-yl)-2-phenylquinoxaline-6-carboxylicacid

Step 1. Methyl3-(4-(N-methylmethan-3-ylsulfonamido)piperidin-1-yl)-2-phenylquinoxaline-6-carboxylate

Into a 50-mL round-bottom flask, was placed a solution of methyl3-(4-(methylamino)piperidin-1-yl)-2-phenylquinoxaline-6-carboxylate (215mg, 0.57 mmol, 1.00 equiv) in dichloromethane (14 mL), methanesulfonylchloride (71.7 mg, 0.63 mmol, 1.10 equiv) and triethylamine (287.85 mg,2.85 mmol, 5.00 equiv). The resulting solution was stirred for 3 h atroom temperature. The reaction was then quenched by the addition of sat.sodium bicarbonate. The resulting solution was concentrated undervacuum. The residue was applied onto a silica gel column with ethylacetate/petroleum ether (1:50). This resulted in 293.5 mg (crude) ofmethyl3-(4-(N-methylmethan-3-ylsulfonamido)piperidin-1-yl)-2-phenylquinoxaline-6-carboxylateas a yellow solid.

LC-MS (ES, m/z): 455[M+H]⁺

Step 2.3-(4-(N-methylmethan-3-ylsulfonamido)piperidin-1-yl)-2-phenylquinoxaline-6-carboxylicacid

Into a 50-mL round-bottom flask, was placed a solution of methyl3-(4-(N-methylmethan-3-ylsulfonamido)piperidin-1-yl)-2-phenylquinoxaline-6-carboxylate(293.5 mg, 0.60 mmol, 1.00 equiv, 93%) in methanol (15 mL). This wasfollowed by the addition of a solution of sodium hydroxide (129.3 mg,3.23 mmol, 5.00 equiv) in water (3 mL) dropwise with stirring. Theresulting solution was stirred overnight at 50° C. in an oil bath. ThepH value of the solution was adjusted to 3-4 with 1N aq. hydrogenchloride. The resulting mixture was concentrated under vacuum. Theresulting solid was washed with methanol and water, filtered and driedunder vacuum. This resulted in 78 mg (29%) of3-(4-(N-methylmethan-3-ylsulfonamido)piperidin-1-yl)-2-phenylquinoxaline-6-carboxylicacid as a yellow solid.

LC-MS (ES, m/z): 441[M+H]⁺

¹H-NMR (300 MHz, DMSO, ppm): δ 8.306 (s, 1H), 8.001-7.986 (d, J=4.5 Hz,4H), 7.587-7.563 (d, J=7.2 Hz, 3H), 3.858-3.774 (t, J=12.6 Hz, 3H),2.905-2.805 (m, 5H), 2.702 (s, 3H), 1.764-1.696 (t, J=10.2 Hz, 2H),1.614-1.580 (d, J=10.2 Hz, 2H).

EXAMPLE 333-(4-(Methylsulfonyl)piperazin-1-yl)-2-phenylquinoxaline-6-carboxylicacid

Step 1. Methyl3-(4-(methylsulfonyl)piperazin-1-yl)-2-phenylquinoxaline-6-carboxylate

Into a 100-mL round-bottom flask, was placed a solution of methyl2-phenyl-3-(piperazin-1-yl)quinoxaline-6-carboxylate (150 mg, 0.43 mmol,1.00 equiv), DIEA (3 mL) in DCM (15 mL). This was followed by theaddition of methanesulfonyl chloride (0.5 mL) at 0° C. The resultingsolution was stirred overnight at room temperature. The reaction waswashed by sat. NaCl and concentrated under vacuum. This resulted in 0.17g (93%) of methyl3-(4-(methylsulfonyl)piperazin-1-yl)-2-phenylquinoxaline-6-carboxylateas a brown yellow oil.

Step 2.3-(4-(Methylsulfonyl)piperazin-1-yl)-2-phenylquinoxaline-6-carboxylicacid

Into a 100-mL round-bottom flask, was placed methyl3-(4-(methylsulfonyl)piperazin-1-yl)-2-phenylquinoxaline-6-carboxylate(170 mg, 0.40 mmol, 1.00 equiv), methanol (15 mL) in dichloromethane (5mL). This was followed by the addition of a solution of sodium hydroxide(190 mg, 4.75 mmol, 11.90 equiv) in water (10 mL). The resultingsolution was stirred for 3 h at room temperature. The resulting mixturewas concentrated under vacuum and diluted by 10 ml of H₂O. The pH valueof the aqueous solution was adjusted to 3 with hydrochloric acid. Theresulting solids were collected by filtration. This resulted in 20 mg(12%) of3-(4-(methylsulfonyl)piperazin-1-yl)-2-phenylquinoxaline-6-carboxylicacid as a brown solid.

LC-MS (ES, m/z): 413 [M+H]⁺

¹H-NMR (300 MHz, DMSO, ppm): δ 13.29 (s, 1H), 8.35-7.57 (m, 8H), 3.18(m, 4H), 2.92 (s, 3H).

EXAMPLE 343-(4-(N-Methylacetamido)piperidin-1-yl)-2-phenylquinoxaline-6-carboxylicacid

Step 1.3-(4-(tert-Butoxycarbonyl)piperidin-1-yl)-2-phenylquinoxaline-6-carboxylicacid

Into a 100-mL round-bottom flask, was placed a solution of methyl3-(4-(tert-butoxycarbonyl)piperidin-1-yl)-2-phenylquinoxaline-6-carboxylate(700 mg, 1.52 mmol, 1.00 equiv) in tetrahydrofuran (50 mL). Then sodiumhydride (300 mg, 12.50 mmol, 8.25 equiv) was added. The resultingmixture was stirred for 1 h at room temperature. To this was added CH₃I(0.5 mL) at 0° C. The resulting solution was stirred 3 h at roomtemperature. The reaction was then quenched by the addition of icewater.The resulting mixture was concentrated under vacuum. This resulted in0.65 g (93%) of3-(4-(tert-butoxycarbonyl)piperidin-1-yl)-2-phenylquinoxaline-6-carboxylicacid as yellow oil.

Step 2. Methyl3-(4-(tert-butoxycarbonyl)piperidin-1-yl)-2-phenylquinoxaline-6-carboxylate

Into a 100-mL round-bottom flask purged and maintained with an inertatmosphere of nitrogen, was placed a solution of3-(4-(tert-butoxycarbonyl)piperidin-1-yl)-2-phenylquinoxaline-6-carboxylicacid (509.7 mg, 1.10 mmol, 1.00 equiv) in N,N-dimethylformamide (15 mL),potassium carbonate (762.3 mg, 5.52 mmol, 5.00 equiv). The resultingsolution was stirred 30 min at room temperature. Then CH₃I (783.3 mg,5.52 mmol, 5.00 equiv) was added dropwise with stirring at 0° C. Theresulting solution was stirred for 3 h at room temperature. The reactionwas then quenched by the addition of water. The resulting aqueoussolution was extracted with 6×20 mL of dichloromethane. The organiclayers combined and dried over anhydrous sodium sulfate and concentratedunder vacuum. This resulted in 285.5 mg (54%) of methyl3-(4-(tert-butoxycarbonyl)piperidin-1-yl)-2-phenylquinoxaline-6-carboxylateas yellow oil.

LC-MS (ES, m/z): 477 [M+H]⁺

¹H-NMR (300 MHz, DMSO, ppm): d 8.67-7.51 (m, 8H), 3.99 (s, 3H), 3.95 (m,1H), 2.74 (s, 3H), 1.45 (s, 9H).

Step 3. Methyl3-(4-(methylamino)piperidin-1-yl)-2-phenylquinoxaline-6-carboxylate

Into a 100-mL round-bottom flask, was placed a solution of methyl3-(4-(tert-butoxycarbonyl)piperidin-1-yl)-2-phenylquinoxaline-6-carboxylate(360 mg, 0.60 mmol, 1.00 equiv, 79%) in dichloromethane (30 mL). Thiswas followed by the addition of trifluoroacetic acid (2 mL) at 0° C. Theresulting solution was stirred for 3 hr at room temperature. Theresulting solution was diluted with 20 ml of H₂O and made pH 9 with sat.NaHCO₃. The aqueous solution was extracted with dichloromethane, theorganic layers combined and concentrated under vacuum.

This resulted in 0.20 g (89%) of methyl3-(4-(methylamino)piperidin-1-yl)-2-phenylquinoxaline-6-carboxylate asbrown red oil.

LC-MS (ES, m/z): 377 [M+H]⁺

Step 4. Methyl3-(4-(N-methylacetamido)piperidin-1-yl)-2-phenylquinoxaline-6-carboxylate

Into a 100-mL round-bottom flask, was placed a solution of methyl3-(4-(methylamino)piperidin-1-yl)-2-phenylquinoxaline-6-carboxylate (76mg, 0.20 mmol, 1.00 equiv) in dichloromethane (15 mL). Then Et₃N (1.25mL) was added. To the above dimethylcarbonate (0.75 mL) was added at 0°C. The resulting solution was stirred for 3 hr at room temperature. Theresulting mixture was concentrated under vacuum. This resulted in 0.077g (91%) of methyl3-(4-(N-methylacetamido)piperidin-1-yl)-2-phenylquinoxaline-6-carboxylateas light yellow oil.

LC-MS (ES, m/z): 419 [M+H]⁺

¹H NMR (300 MHz, DMSO): δ 8.54-7.51 (m, 8H), 4.01 (s, 3H), 2.87 (s, 3H).

Step 5.3-(4-(N-Methylacetamido)piperidin-1-yl)-2-phenylquinoxaline-6-carboxylicacid

Into a 100-mL round-bottom flask, was placed a solution of methyl3-(4-(N-methylacetamido)piperidin-1-yl)-2-phenylquinoxaline-6-carboxylate(77 mg, 0.18 mmol, 1.00 equiv) in MeOH (15 mL). Then dichloromethane (5mL) was added. Finally to the above was added a solution of sodiumhydroxide (700 mg, 17.50 mmol, 95.00 equiv) in water (3 mL). Theresulting solution was stirred for 3 hr at room temperature. Theresulting mixture was concentrated under vacuum, diluted with 10 ml ofH₂O. The pH value of the aqueous solution was adjusted to 3 with aq. 3Nhydrochloric acid. The resulting solids were collected by filtration.This resulted in 52 mg (70%) of3-(4-(N-methylacetamido)piperidin-1-yl)-2-phenylquinoxaline-6-carboxylicacid as a yellow solid.

LC-MS (ES, m/z): 405 [M+H]⁺

¹H NMR (300 MHz, DMSO): δ 13.27 (s, 1H), 8.31-7.54 (m, 8H), 4.44-4.41(m, 1H), 3.87-3.82 (m, 2H), 2.93-2.67 (m, 5H), 2.05-1.98 (m, 3H),1.78-1.40 (m, 4H).

EXAMPLE 353-(4-(Methyl(phenyl)amino)piperidin-1-yl)-2-phenylquinoxaline-6-carboxylicacid

Step 1. Methyl2-phenyl-3-(4-(phenylamino)piperidin-1-yl)quinoxaline-6-carboxylate

Into a 100-mL round-bottom flask purged and maintained with an inertatmosphere of nitrogen, was placed a solution of methyl3-(4-oxopiperidin-1-yl)-2-phenylquinoxaline-6-carboxylate (329.7 mg,0.91 mmol, 1.00 equiv) in isopropanol (12 mL). Then aniline (255.2 mg,2.74 mmol, 3.00 equiv) and acetic acid (221.8 mg, 3.70 mmol, 4.00 equiv)was added dropwise with stirring. The resulting solution was stirred for1 h at 60° C. in an oil bath. To the above NaHB(OAc)₃ (968.1 mg, 4.57mmol, 4.57 equiv) was added at 0° C. The resulting solution was stirredfor an additional 3 h at room temperature. The reaction was thenquenched by the addition of water. The resulting aqueous solution wasextracted with 6×20 mL of dichloromethane. The organic layers werecombined and dried over sodium sulfate and concentrated under vacuum.The residue was applied onto a silica gel column with DCM/MeOH (30:1).This resulted in 297.4 mg (74%) of methyl2-phenyl-3-(4-(phenylamino)piperidin-1-yl)quinoxaline-6-carboxylate as ayellow solid.

LC-MS (ES, m/z): 439 [M+H]⁺

Step 2.3-(4-(Methyl(phenyl)amino)piperidin-1-yl)-2-phenylquinoxaline-6-carboxylicacid

Into a 50-mL round-bottom flask, was placed a solution of methyl2-phenyl-3-(4-(phenylamino)piperidin-1-yl)quinoxaline-6-carboxylate(297.4 mg, 0.68 mmol, 1.00 equiv) in tetrahydrofuran (16 mL). Thensodium hydride (163 mg, 6.79 mmol, 10.00 equiv) and CH₃I (964 mg, 6.79mmol, 10.00 equiv) was added. The resulting solution was stirred for 2days at room temperature. The reaction was then quenched by the additionof water. The resulting aqueous solution was extracted with 5×30 mL ofdichloromethane. The organic layers were combined and concentrated undervacuum. The crude product (150 mg) was purified by Prep-HPLC with thefollowing conditions (AGILENT Pre-HPLC (UV-Directed): Column, SunFirePrep C18, 19*150 mm 5 um; mobile phase, water with 0.05% TFA and CH₃CN(25% CH₃CN up to 60% in 6 min, up to 100% in 1 min); Detector, UV 254nm. 30 mg of product was obtained. This resulted in 30 mg (10%) of3-(4-(methyl(phenyl)amino)piperidin-1-yl)-2-phenylquinoxaline-6-carboxylicacid as a yellow solid.

LC-MS (ES, m/z): 439[M+H]⁺

¹H-NMR (300 MHz, DMSO, ppm) 8.307 (s, 1H), 8.026-8.001 (d, J=7.5 Hz,4H), 7.591-7.539 (t, J=7.8 Hz, 3H), 7.190-7.138 (t, J=7.8 Hz, 2H),6.827-6.800 (d, J=8.1 Hz, 2H), 6.652-6.603 (t, J=7.35 Hz, 1H),3.885-3.845 (d, J=12 Hz, 4H), 2.965-2.885 (t, J=24 Hz, 2H), 2.713 (s,3H), 1.769-1.736 (d, J=9.9 Hz, 2H), 1.596-1.561 (d, J=10.5 Hz, 2H).

EXAMPLE 36 3-(Diethylamino)-2-phenylquinoxaline-6-carboxylic acid

Step 1. Methyl 3-(diethylamino)-2-phenylquinoxaline-6-carboxylate

Into a 8-mL sealed tube, was placed a solution of methyl3-bromo-2-phenylquinoxaline-6-carboxylate (150 mg, 0.44 mmol, 1.00equiv) in N,N-dimethylformamide (3 mL), diethylamine (63.4 mg, 0.87mmol, 2.00 equiv), and DIEA (170.3 mg, 1.32 mmol, 3.00 equiv). Theresulting solution was stirred overnight at 100° C. in an oil bath. Theresulting solution was concentrated under vacuum. The residue wasapplied onto a silica gel column and eluted with ethyl acetate/petroleumether (1:100). This resulted in 117 mg (80%) of methyl3-(diethylamino)-2-phenylquinoxaline-6-carboxylate as a yellow oil.

LC-MS (ES, m/z): 336 [M+H]⁺

Step 2. 3-(Diethylamino)-2-phenylquinoxaline-6-carboxylic acid

Into a 50-mL round-bottom flask, was placed a solution of methyl3-(diethylamino)-2-phenylquinoxaline-6-carboxylate (117 mg, 0.35 mmol,1.00 equiv) in methanol (15 mL). This was followed by the addition of asolution of sodium hydroxide (69.9 mg, 1.75 mmol, 5.00 equiv) in water(2 mL) dropwise with stirring. The resulting solution was stirredovernight at 50° C. in an oil bath. The pH value of the solution wasadjusted to 3-4 with 1N hydrogen chloride. The resulting mixture wasconcentrated under vacuum. The crude product (110 mg) was purified byPrep-HPLC with the following conditions: Column, SunFire Prep C18, 5 um,19*150 mm; mobile phase, water with 0.05% TFA and methanol (70% methanolup to 90% in 10 min); Detector, UV 254 nm. This resulted in 70 mg (62%)of 3-(diethylamino)-2-phenylquinoxaline-6-carboxylic acid as a yellowsolid.

LC-MS (ES, m/z): 322 [M+H]⁺

¹H NMR (300 MHz, DMSO, ppm): δ 13.24 (s, 1H), 8.28 (s, 1H), 7.95 (s,2H), 7.85-7.82 (t, J=4.5 Hz, 2H), 7.58-7.49 (m, 3H), 3.30-3.28 (d, J=6Hz, 4H), 1.04-0.99 (t, J=7.5 Hz, 6H).

EXAMPLE 373-(4-Acetamidopiperidin-1-yl)-2-phenylquinoxaline-6-carboxylic acid

Step 1. Methyl3-(4-(tert-Butoxycarbonyl)piperidin-1-yl)-2-phenylquinoxaline-6-carboxylate

Into an 8-mL sealed tube, was placed methyl3-bromo-2-phenylquinoxaline-6-carboxylate (200 mg, 0.58 mmol, 1.00equiv), tert-butyl piperidin-4-yl carbamate (300 mg, 1.50 mmol, 2.58equiv), DIEA (300 mg, 2.33 mmol, 3.98 equiv), and DMSO (2 mL). Theresulting solution was stirred overnight at 100° C. The resultingsolution was diluted with ethyl acetate. The resulting solution waswashed with sat. sodium chloride, then concentrated under vacuum. Thisresulted in 0.2 g (74%) of methyl3-(4-(tert-butoxycarbonyl)piperidin-1-yl)-2-phenylquinoxaline-6-carboxylateas a light yellow solid.

Step 2. Methyl3-(4-aminopiperidin-1-yl)-2-phenylquinoxaline-6-carboxylate

Into a 100-mL round-bottom flask, was placed a solution of methyl3-(4-(tert-butoxycarbonyl)piperidin-1-yl)-2-phenylquinoxaline-6-carboxylate(150 mg, 0.31 mmol, 1.00 equiv, 95%) in dichloromethane (15 mL). Thiswas followed by the addition of trifluoroacetic acid (2 mL) at 0° C. Theresulting solution was stirred for 3 h at room temperature. Theresulting mixture was concentrated under vacuum. The resulting solutionwas diluted with 10 ml of H₂O. The pH value of the aqueous solution wasadjusted to 8 with sat. sodium bicarbonate. The resulting aqueoussolution was extracted with dichloromethane. The organic layers combinedand concentrated under vacuum. This resulted in 0.06 g (53%) of methyl3-(4-aminopiperidin-1-yl)-2-phenylquinoxaline-6-carboxylate as a lightyellow solid.

Step 3. Methyl3-(4-acetamidopiperidin-1-yl)-2-phenylquinoxaline-6-carboxylate

Into a 50-mL round-bottom flask, was placed a solution of methyl3-(4-aminopiperidin-1-yl)-2-phenylquinoxaline-6-carboxylate (100 mg,0.28 mmol, 1.00 equiv) in dichloromethane (50 mL). This was followed bythe addition of triethylamine (7 mL) and acetic anhydride (1 mL) at 0°C. The resulting solution was stirred overnight at room temperature andconcentrated under vacuum. This resulted in 0.1 g (90%) of methyl3-(4-acetamidopiperidin-1-yl)-2-phenylquinoxaline-6-carboxylate as lightyellow oil.

Step 4. 3-(4-Acetamidopiperidin-1-yl)-2-phenylquinoxaline-6-carboxylicacid

Into a 100-mL round-bottom flask was placed methyl3-(4-acetamidopiperidin-1-yl)-2-phenylquinoxaline-6-carboxylate (100 mg,0.25 mmol, 1.00 equiv), methanol (15 mL), dichloromethane (7 mL). Tothis was added a solution of sodium hydroxide (1.5 g, 37.50 mmol, 151.50equiv) in water (7 mL). The resulting solution was stirred for 3 h atroom temperature. The resulting mixture was concentrated under vacuumand diluted with 10 ml of H₂O. The pH of the aqueous solution wasadjusted to 3 with hydrochloric acid. The resulting solids werecollected by filtration. This resulted in 95 mg (94%) of3-(4-acetamidopiperidin-1-yl)-2-phenylquinoxaline-6-carboxylic acid as alight yellow solid.

LC-MS (ES, m/z): 391 [M+H]⁺

¹H-NMR (300 MHz, DMSO, ppm): δ 8.30 (m, 1H), 7.99-7.98 (m, 4H),7.84-7.82 (m, 1H), 7.56-7.55 (m, 3H), 3.71-3.61 (m, 3H), 2.92-2.85 (m,2H), 1.78 (s, 3H), 1.73-1.70 (m, 2H), 1.46-1.39 (m, 2H).

EXAMPLE 383-(N-Methylmethan-5-ylsulfonamido)-2-phenylquinoxaline-6-carboxylic acid

Step 1. Methyl3-(N-methylmethan-5-ylsulfonamido)-2-phenylquinoxaline-6-carboxylate

Into a 10-mL sealed tube, was placed methyl3-bromo-2-phenylquinoxaline-6-carboxylate (200 mg, 0.58 mmol, 1.00equiv), N-methylmethanesulfonamide (381 mg, 3.49 mmol, 3.00 equiv),K₃PO₄ (370 mg, 1.75 mmol, 3.00 equiv), CuI (110 mg, 0.58 mmol, 1.00equiv), N1,N1,N2,N2-tetramethylethane-1,2-diamine (67 mg, 0.58 mmol,1.00 equiv), 1,4-dioxane (5 mL). The resulting solution was stirredovernight at 100 degrees C. in an oil bath. The resulting mixture wasconcentrated under vacuum. The residue was applied onto a silica gelcolumn with PE:EA (20:1). This resulted in 110 mg (51%) of methyl3-(N-methylmethan-5-ylsulfonamido)-2-phenylquinoxaline-6-carboxylate asa yellow solid.

LC-MS (ES, m/z): 372 [M+H]⁺

Step 2.3-(N-methylmethan-5-ylsulfonamido)-2-phenylquinoxaline-6-carboxylic acid

Into a 50-mL round-bottom flask, was placed methyl3-(N-methylmethan-5-ylsulfonamido)-2-phenylquinoxaline-6-carboxylate(130 mg, 0.35 mmol, 1.00 equiv), LiOH (16.8 mg, 0.70 mmol, 2.00 equiv),methanol (10 mL), water (2 ml), dichloromethane (2 ml). The resultingsolution was stirred for 2 hs at 50° C. in an oil bath. The resultingmixture was concentrated under vacuum. The resulting solution wasdiluted with 20 ml of H2O. The resulting solution was extracted with2×20 ml of dichloromethane and the aqueous layers combined. The pH valueof the solution was adjusted to 4 with aq hydrogen chloride (1 mol/L).The solids were collected by filtration. This resulted in 80 mg (63%) of3-(N-methylmethan-5-ylsulfonamido)-2-phenylquinoxaline-6-carboxylic acidas a yellow solid.

LC-MS (ES, m/z): 358 [M+H]⁺

¹H-NMR (300 MHz, DMSO, ppm): δ 8.645 (s, 1H), 8.366-8.338 (d, J=8.4 Hz,1H), 8.266-8.237 (d, J=8.7 Hz, 1H), 7.944-7.913 (m, 2H), 7.612-7.577 (m,3H), 3.269 (s, 3H), 3.141 (s, 3H).

EXAMPLE 393-(3,4-Dihydroisoquinolin-2(1H)-yl)-2-phenylquinoxaline-6-carboxylicacid

Step 1. Methyl3-(3,4-dihydroisoquinolin-2(1H)-yl)-2-phenylquinoxaline-6-carboxylate

Into a 8-mL sealed tube, was placed a solution of methyl3-bromo-2-phenylquinoxaline-6-carboxylate (130 mg, 0.38 mmol, 1.00equiv), N,N-dimethylformamide (5 mL), 1,2,3,4-tetrahydroisoquinoline(101.1 mg, 0.76 mmol, 2.00 equiv), potassium carbonate (157.3 mg, 1.14mmol, 3.00 equiv). The resulting solution was stirred for overnight at100° C. The reaction was then quenched by the addition of water. Theresulting solids were collected by filtration. This resulted in 110 mg(70%) of methyl3-(3,4-dihydroisoquinolin-2(1H)-yl)-2-phenylquinoxaline-6-carboxylate asa yellow solid.

LC-MS: (ES, m/z): 396 [M+H]⁺

Step 2.3-(3,4-dihydroisoquinolin-2(1H)-yl)-2-phenylquinoxaline-6-carboxylicacid

Into a 50-mL round-bottom flask, was placed a solution of methyl3-(3,4-dihydroisoquinolin-2(1H)-yl)-2-phenylquinoxaline-6-carboxylate(110 mg, 0.26 mmol, 1.00 equiv, 95%) in methanol (15 mL). This wasfollowed by the addition of a solution of sodium hydroxide (55.7 mg,1.39 mmol, 5.00 equiv) in water (1.5 mL) dropwise with stirring. Theresulting solution was stirred for overnight at 50° C. in an oil bath.The resulting solution was concentrated under vacuum. The residue wasdiluted with water. The pH value of the aqueous solution was adjusted to3-4 with 1N hydrogen chloride. The resulting solids were collected byfiltration and washed with methanol. This resulted in 68.1 mg (66%) of3-(3,4-dihydroisoquinolin-2(1H)-yl)-2-phenylquinoxaline-6-carboxylicacid as a yellow solid.

LC-MS: (ES, m/z): 382 [M+H]⁺

¹H-NMR (300 MHz, DMSO, ppm) 8.36 (s, 1H), 8.00-7.93 (m, 4H), 7.58-7.55(t, J=4.5 Hz, 3H), 7.18-7.14 (m, 4H), 4.57 (s, 2H), 3.39-3.36 (d, J=9Hz, 2H), 2.72-2.70 (d, J=6 Hz, 2H).

EXAMPLE 40 3-(3,4-Dihydroquinolin-1(2H)-yl)-2-phenylquinoxaline-6-carboxylic acid

Step 1. Synthesis of 3-(2-bromophenyl)propanenitrile

Into a 500-mL 3-necked round-bottom flask, was placed a solution ofacetonitrile (49 g, 1.20 mol, 9.96 equiv) in tetrahydrofuran (150 mL).This was followed by the addition of BuLi (72 mL, 1.50 equiv) dropwisewith stirring at −78° C. Stirred at −78° C. for 1 h. To this was added asolution of 1-bromo-2-(bromomethyl)benzene (30 g, 120.00 mmol, 1.00equiv) in tetrahydrofuran (100 mL) dropwise with stirring at −78° C. Theresulting solution was stirred for 1 h at −78° C. The reaction wasquenched by the addition of 100 mL of water at −78° C. The resultingaqueous solution was extracted with 3×100 mL of ethyl acetate and theorganic layers combined and dried over anhydrous sodium sulfate andconcentrated under vacuum. The residue was applied onto a silica gelcolumn with ethyl acetate/petroleum ether (1:20). The crude product waspurified by distillation under reduced pressure (2 mm Hg) and thefraction was collected at 98-107° C. This resulted in 13.21 g (52%) of3-(2-bromophenyl)propanenitrile as colorless oil.

GC-MS: (ES, m/z): 209 [M]⁺

¹H-NMR (300 MHz, CDCl₃, ppm) 7.61-7.58 (d, J=7.8 Hz, 1H), 7.35-7.29 (m,2H), 7.22-7.15 (m, 1H), 3.15-3.09 (t, J=7.5 Hz, 2H), 2.73-2.68 (t, J=7.5Hz, 2H).

Step 2. 3-(2-Bromophenyl)propan-1-amine

Into a 250-mL 3-necked round-bottom flask, was placed a solution of3-(2-bromophenyl)propanenitrile (2.1 g, 10.00 mmol, 1.00 equiv) intetrahydrofuran (20 mL). This was followed by the addition of borane (1mol/L in THF, 50 mL, 5.00 equiv) dropwise with stirring at 0° C. Theresulting solution was stirred for overnight at room temperature. Thereaction was then quenched by the addition of 50 mL of water at 0° C.and extracted with 3×50 mL of ethyl acetate. The organic layers werecombined and dried over anhydrous sodium sulfate and concentrated undervacuum. The residue was dissolved in 30 mL of 6N aqueous hydrogenchloride. The aqueous solution was extracted with 30 mL of ethyl acetateand the aqueous layers were combined. The pH value of the aqueoussolution was adjusted to 10 with 10% aqueous sodium hydroxide. Theresulting solution was extracted with 3×50 mL of ethyl acetate. Theorganic layers were combined and dried over anhydrous sodium sulfate,concentrated under vacuum. This resulted in 1.3 g (58%) of3-(2-bromophenyl)propan-1-amine as colorless oil.

LC-MS: (ES, m/z): 214 [M+H]⁺

Step 3. Methyl3-(3-(2-bromophenyl)propylamino)-2-phenylquinoxaline-6-carboxylate

Into a 20-mL sealed tube, was placed methyl3-chloro-2-phenylquinoxaline-6-carboxylate (180 mg, 0.60 mmol, 1.00equiv), toluene/DMSO (5/1 mL), 3-(2-bromophenyl)propan-1-amine (385 mg,1.80 mmol, 2.99 equiv), and potassium carbonate (414 mg, 3.00 mmol, 4.98equiv). The resulting solution was stirred overnight at 100° C. Themixture was concentrated under vacuum. The residue was purified bysilica gel chromatography with ethyl acetate/petroleum ether (1:50).This resulted in 240 mg (80%) of methyl3-(3-(2-bromophenyl)propylamino)-2-phenylquinoxaline-6-carboxylate as ayellow solid.

LC-MS: (ES, m/z): 476 [M+H]⁺

¹H-NMR (300 MHz, DMSO, ppm): δ 1.99-1.91 (m, 2H), 2.81-2.75 (t, J=7.8Hz, 2H), 3.54-3.47 (m, 2H), 3.92 (s, 3H), 6.97-6.93 (t, J=5.4 Hz, 1H),7.17-7.11 (m, 1H), 7.34-7.28 (m, 1H), 7.43-7.39 (dd, J=1.5, 7.6 Hz, 4H),7.69-7.54 (m, 2H), 7.90-7.68 (m, 2H), 7.15 (m, 1H).

Step 4. Methyl3-(3,4-dihydroquinolin-1(2H)-yl)-2-phenylquinoxaline-6-carboxylate

Into a 20-mL sealed tube, was placed a solution of methyl3-(3-(2-bromophenyl)propylamino)-2-phenylquinoxaline-6-carboxylate (240mg, 0.50 mmol, 1.00 equiv) in dioxane (10 mL), CsCO₃ (490 mg, 1.50 mmol,3.00 equiv), Pd₂(dba)₃ (46 mg, 0.05 mmol, 0.10 equiv) and BINAP (125 mg,0.20 mmol, 0.40 equiv) were added. The resulting solution was stirredovernight at 100° C. The mixture was concentrated under vacuum andpurified by flash column chromatography with ethyl acetate/petroleumether (1:50). This resulted in 180 mg (86%) of methyl3-(3,4-dihydroquinolin-1(2H)-yl)-2-phenylquinoxaline-6-carboxylate as ayellow solid.

LC-MS: (ES, m/z): 396 [M+H]⁺

¹H-NMR (300 MHz, DMSO, ppm): δ 8.37 (s, 1H), 8.10 (d, J=0.9 Hz, 2H),7.83-7.77 (m, 1H), 7.74-7.70 (m, 2H), 7.49-7.45 (m, 1H), 7.29-7.26 (m,3H), 6.99-6.95 (m, 1H), 6.74-6.61 (m, 3H), 3.95 (s, 1H), 3.76-3.70 (t,J=6.6 Hz, 2H), 2.75-2.70 (t, J=6.6 Hz, 2H), 2.03-1.94 (m, 2H).

Step 5.3-(3,4-Dihydroquinolin-1(2H)-yl)-2-phenylquinoxaline-6-carboxylic acid

Into a 50-mL round-bottom flask, was placed a solution of methyl3-(3,4-dihydroquinolin-1(2H)-yl)-2-phenylquinoxaline-6-carboxylate (100mg, 0.25 mmol, 1.00 equiv), sodium hydroxide (20 mg, 0.5 mmol, 2.00equiv), and methanol/H₂O (20/5 mL). The resulting solution was heated toreflux for 4 hrs and then concentrated to dryness. The residue wasdiluted with 15 mL water and acidified to pH=5 with 3N aq. HCl. Theresulting solid was collected by filtration, washed with water, anddried to afford 65 mg (65%) of3-(3,4-dihydroquinolin-1(2H)-yl)-2-phenylquinoxaline-6-carboxylic acidas an orange solid.

LC-MS: (ES, m/z): 382 [M+H]⁺

¹H-NMR (300 MHz, DMSO, ppm): δ 8.35 (s, 1H), 8.14-8.06 (d, J=0.9 Hz,2H), 7.74-7.70 (m, 2H), 7.29-7.26 (t, J=2.7 Hz, 3H), 6.99-6.95 (t, J=6.3Hz, 1H), 6.74-6.60 (m, 3H), 3.80-3.75 (t, J=6.3 Hz, 2H), 2.75-2.70 (t,J=6.3 Hz, 2H), 2.02-1.93 (m, 2H).

EXAMPLE 41 3-(Phenethylamino)-2-phenylquinoxaline-6-carboxylic acid

Step 1. Methyl 3-(phenethylamino)-2-phenylquinoxaline-6-carboxylate

Into a 10-mL sealed tube, was placed methyl3-bromo-2-phenylquinoxaline-6-carboxylate (150 mg, 0.44 mmol, 1.00equiv), 2-phenylethanamine hydrochloride (207.8 mg, 1.32 mmol, 3.00equiv), potassium carbonate (304.4 mg, 2.21 mmol, 5.00 equiv),N,N-dimethylformamide (2 mL). The resulting solution was stirredovernight at 100° C. in an oil bath. The reaction was then quenched bythe addition of 20 mL of water. The resulting solution was extractedwith 3×50 mL of ethyl acetate and the organic layers combined. Theorganic layer was dried over anhydrous sodium sulfate and concentratedunder vacuum. The residue was applied onto a silica gel column withethyl acetate/petroleum ether (1:50). This resulted in 120 mg (71%) ofmethyl 3-(phenethylamino)-2-phenylquinoxaline-6-carboxylate as a yellowsolid.

LC-MS: (ES, m/z): 384 [M+H]⁺

Step 2. 3-(Phenethylamino)-2-phenylquinoxaline-6-carboxylic acid

Into a 50-mL round-bottom flask (1 atm), was placed a solution of methyl3-(phenethylamino)-2-phenylquinoxaline-6-carboxylate (120 mg, 0.31 mmol,1.00 equiv) in methanol (15 mL), a solution of sodium hydroxide (50.08g, 1.25 mol, 4.00 equiv) in water (2 mL). The resulting solution wasstirred for 2 h at 50° C. in an oil bath. The resulting mixture wasconcentrated under vacuum. The residue was diluted in 20 mL of water.The pH value of the solution was adjusted to 4-5 with aq hydrogenchloride (1 mol/L). The resulting solids were collected by filtration.This resulted in 60 mg (52%) of3-(phenethylamino)-2-phenylquinoxaline-6-carboxylic acid as a yellowsolid.

LC-MS: (ES, m/z): 370 [M+H]⁺

¹H NMR (300 MHz, DMSO, ppm): δ 8.203-8.199 (s, 1H), 7.855 (s, 2H),7.662-7.630 (m, 2H), 7.569-7.515 (m, 3H), 7.349-7.194 (m, 5H),6.809-6.773 (m, 1H), 3.706-3.639 (m, 2H), 2.982-2.933 (m, 2H).

EXAMPLE 42 3-(Methyl(phenethyl)amino)-2-phenylquinoxaline-6-carboxylicacid

Step 1. N-Phenethylformamide

Into a 100-mL 3-necked round-bottom flask purged and maintained with aninert atmosphere of nitrogen, was placed 2-phenylethanamine (1.9 g,15.70 mmol, 1.00 equiv). This was followed by the addition of ethylformate (5 g, 67.57 mmol, 4.30 equiv) dropwise with stirring. Theresulting solution was stirred overnight at 50° C. The resultingsolution was concentrated under vacuum. The residue was applied onto asilica gel column with dichloromethane/methanol (70:1). This resulted in2.27 g (97%) of N-phenethylformamide as yellow oil.

LC-MS: (ES, m/z): 150 [M+H]⁺

Step 2. N-Methyl-2-phenylethanamine

Into a 250-mL 3-necked round-bottom flask purged and maintained with aninert atmosphere of nitrogen, was placed a solution of LiAlH₄ (868 mg,22.84 mmol, 1.50 equiv) in tetrahydrofuran (70 mL). This was followed bythe addition of a solution of N-phenethylformamide (2.27 g, 15.23 mmol,1.00 equiv) in tetrahydrofuran (50 mL) dropwise with stirring while theresulting solution maintained reflux. The resulting solution was stirredovernight at reflux in an oil bath. The reaction was then quenched bythe addition of water. The resulting solution was extracted with 4×30 mLof dichloromethane and the organic layers combined and dried overanhydrous sodium sulfate and concentrated under vacuum. The residue wasapplied onto a silica gel column with dichloromethane/methanol (100:1).This resulted in 1.36 g (34%) of N-methyl-2-phenylethanamine as yellowoil.

Step 3. Methyl3-(methyl(phenethyl)amino)-2-phenylquinoxaline-6-carboxylate

Into a 8-mL sealed tube, was placed a solution of methyl3-bromo-2-phenylquinoxaline-6-carboxylate (150 mg, 0.44 mmol, 1.00equiv) in N,N-dimethylformamide (5 mL), N-methyl-2-phenylethanamine(177.6 mg, 1.32 mmol, 3.00 equiv), potassium carbonate (181.6 mg, 1.32mmol, 3.00 equiv). The resulting solution was stirred overnight at 100°C. in an oil bath. The reaction was then quenched by the addition ofwater. The resulting solution was extracted with 3×20 mL ofdichloromethane and the organic layers combined and dried over anhydroussodium sulfate and concentrated under vacuum. The residue was appliedonto a silica gel column with ethyl acetate/petroleum ether (100:1).This resulted in 153.3 mg (85%) of methyl3-(methyl(phenethyl)amino)-2-phenylquinoxaline-6-carboxylate as a yellowsolid.

LC-MS: (ES, m/z): 398 [M+H]⁺

¹H-NMR (300 MHz, CDCl₃, ppm): δ 8.52-8.51 (d, J=3 Hz, 1H), 8.06-8.05 (d,J=3 Hz, 1H), 8.03-8.02 (d, J=3 Hz, 1H), 8.00-7.65 (m, 2H), 7.48-7.42 (m,3H), 7.24-7.05 (m, 3H), 7.04-7.02 (d, J=6 Hz, 2H), 3.99 (s, 3H),3.63-3.58 (t, J=7.5 Hz, 2H), 2.90-2.74 (m, 5H).

Step 4. 3-(Methyl(phenethyl)amino)-2-phenylquinoxaline-6-carboxylic acid

Into a 50-mL round-bottom flask, was placed a solution of methyl3-(methyl(phenethyl)amino)-2-phenylquinoxaline-6-carboxylate (144.7 mg,0.35 mmol, 1.00 equiv, 96%) in methanol (20 mL). This was followed bythe dropwise addition of a solution of sodium hydroxide (72.9 mg, 1.82mmol, 5.00 equiv) in water (2 mL) with stirring. The resulting solutionwas stirred overnight at 50° C. in an oil bath. Then it was concentratedunder vacuum and diluted with 10 ml of water. The pH value of theaqueous solution was adjusted to 3-4 with 1N aq. hydrogen chloride. Theresulting solid was collected by filtration and washed with methanol.This resulted in 52.6 mg (38%) of3-(methyl(phenethyl)amino)-2-phenylquinoxaline-6-carboxylic acid as ayellow solid.

LC-MS: (ES, m/z): 384 [M+H]⁺

¹H-NMR (300 MHz, DMSO, ppm): δ 8.28 (s, 1H), 7.96-7.89 (m, 2H),7.65-7.62 (m, 2H), 7.50-7.48 (t, J=3 Hz, 3H), 7.22-7.03 (m, 5H),3.57-3.52 (t, J=7.5 Hz, 2H), 2.89-2.79 (m, 5H).

EXAMPLE 43 3-(Isopropyl(methyl)amino)-2-phenylquinoxaline-6-carboxylicacid

Step 1. Methyl3-(isopropyl(methyl)amino)-2-phenylquinoxaline-6-carboxylate

Into a 8-mL sealed tube, was placed a solution of methyl3-bromo-2-phenylquinoxaline-6-carboxylate (170 mg, 0.50 mmol, 1.00equiv) in N,N-dimethylformamide (5 mL), N-methylpropan-2-amine (73 mg,1.00 mmol, 2.00 equiv), and potassium carbonate (207 mg, 1.50 mmol, 3.00equiv). The resulting solution was stirred overnight at 100° C. Thereaction was then quenched by the addition of water. The resultingsolids were collected by filtration. This resulted in 109.8 mg (59%) ofmethyl 3-(isopropyl(methyl)amino)-2-phenylquinoxaline-6-carboxylate as ayellow solid.

LC-MS: (ES, m/z): 336 [M+H]⁺

Step 2. 3-(Isopropyl(methyl)amino)-2-phenylquinoxaline-6-carboxylic acid

Into a 50-mL round-bottom flask, was placed a solution of methyl3-(isopropyl(methyl)amino)-2-phenylquinoxaline-6-carboxylate (109.8 mg,0.29 mmol, 1.00 equiv, 90%) in methanol (20 mL). This was followed bythe dropwise addition of a solution of sodium hydroxide (65.6 mg, 1.64mmol, 5.00 equiv) in water (3 mL) with stirring. The resulting solutionwas stirred overnight at 50° C. in an oil bath. The pH value of thesolution was adjusted to 3-4 with 1N hydrogen chloride. The filtrate wasconcentrated under vacuum. The resulting solids were collected byfiltration and washed with methanol and water. This resulted in 58 mg(59%) of 3-(isopropyl(methyl)amino)-2-phenylquinoxaline-6-carboxylicacid as a yellow solid.

LC-MS: (ES, m/z): 322 [M+H]⁺

¹H-NMR (300 MHz, DMSO, ppm): δ 8.26 (s, 1H), 7.94 (s, 2H), 7.86-7.83 (m2H), 7.58-7.50 (m, 3H), 4.25-4.16 (m, 1H), 2.67 (s, 3H), 1.05-1.02 (d,J=9 Hz, 6H).

EXAMPLE 44 3-(Cyclohexylamino)-2-phenylquinoxaline-6-carboxylic acid

Step 1. Methyl 3-(cyclohexylamino)-2-phenylquinoxaline-6-carboxylate

Into a 10-mL sealed tube, was placed methyl3-bromo-2-phenylquinoxaline-6-carboxylate (150 mg, 0.44 mmol, 1.00equiv), cyclohexanamine (131.03 mg, 1.32 mmol, 3.00 equiv), potassiumcarbonate (304.41 mg, 2.21 mmol, 5.00 equiv), and N,N-dimethylformamide(2 mL). The resulting solution was stirred overnight at 100° C. in anoil bath. The reaction was then quenched by the addition of 20 mL ofwater. The resulting aqueous solution was extracted with 3×50 mL ofethyl acetate. The organic layers were combined and washed with 5×30 mLof aq. sodium chloride. The organic layers were dried over anhydroussodium sulfate and concentrated in vacuo. The residue was purified bysilica gel chromatography with ethyl acetate/petroleum ether (1:50).This resulted in 80 mg (46%) of methyl3-(cyclohexylamino)-2-phenylquinoxaline-6-carboxylate as a yellow solid.

LC-MS: (ES, m/z): 362 [M+H]⁺

Step 2. 3-(Cyclohexylamino)-2-phenylquinoxaline-6-carboxylic acid

Into a 50-mL round-bottom flask, was placed a solution of methyl3-(cyclohexylamino)-2-phenylquinoxaline-6-carboxylate (80 mg, 0.22 mmol,1.00 equiv) in methanol (15 mL), a solution of sodium hydroxide (44.32mg, 1.11 mmol, 5.00 equiv) in water (2 mL). The resulting solution wasstirred for 2 hrs at 50° C. in an oil bath. The resulting mixture wasconcentrated under vacuum. The residue was diluted in 20 mL of water.The pH value of the solution was adjusted to 4-5 with aq hydrogenchloride (1 mol/L). The resulting solids were collected by filtration.This resulted in 60 mg (76%) of3-(cyclohexylamino)-2-phenylquinoxaline-6-carboxylic acid as a yellowsolid.

LC-MS (ES, m/z): 334 [M+H]⁺

¹H-NMR (300 MHz, DMSO, ppm): δ 8.155 (s, 1H), 7.879-7.850 (d, J=8.7 Hz,2H), 7.815-7.772 (m, 2H), 7.597-7.578 (m, 3H), 6.248-6.222 (d, J=8.4 Hz,1H), 4.091 (s, 1H), 1.966 (m, 2H), 1.694-1.598 (m, 3H), 1.370 (m, 4H),1.239-1.181 (m, 1H).

EXAMPLE 45 3-(2-Methylpiperidin-1-yl)-2-phenylquinoxaline-6-carboxylicacid

Step 1. Methyl3-(2-methylpiperidin-1-yl)-2-phenylquinoxaline-6-carboxylate

Into a 8-mL sealed tube, was placed methyl3-bromo-2-phenylquinoxaline-6-carboxylate (150 mg, 0.44 mmol, 1.00equiv), 2-methylpiperidine (130.86 mg, 1.32 mmol, 3.00 equiv), DIEA(170.28 mg, 1.32 mmol, 3.00 equiv), N,N-dimethylformamide (4 mL). Theresulting solution was stirred overnight at 100° C. in an oil bath. Thereaction was then quenched by the addition of water. The resultingsolution was extracted with 4×20 mL of dichloromethane and the organiclayers combined and dried over anhydrous sodium sulfate. The resultingmixture was concentrated under vacuum. The residue was applied onto asilica gel column with ethyl acetate/petroleum ether (1:7). Thisresulted in 60 mg (36%) of methyl3-(2-methylpiperidin-1-yl)-2-phenylquinoxaline-6-carboxylate as yellowoil.

LC-MS: (ES, m/z): 362 [M+H]⁺

¹H-NMR (300 MHz, CDCl₃, ppm): δ 8.580-8.575 (s, 1H), (d, J=1.5 Hz, 1H),8.10-7.98 (m, 4H), 7.56-7.48 (m, 3H), 4.18-4.14 (t, J=6 Hz, 1H), 4.01(s, 3H), 3.20-3.12 (m, 1H), 1.76-1.61 (m, 6H), 1.14-1.12 (d, J=6.9 Hz,3H).

Step 2. 3-(2-Methylpiperidin-1-yl)-2-phenylquinoxaline-6-carboxylic acid

Into a 50-mL round-bottom flask, was placed a solution of methyl3-(2-methylpiperidin-1-yl)-2-phenylquinoxaline-6-carboxylate (107.9 mg,0.30 mmol, 1.00 equiv) in methanol (20 mL). This was followed by thedropwise addition of a solution of sodium hydroxide (60 mg, 1.50 mmol,5.00 equiv) in water (3 mL) with stirring. The resulting solution wasstirred overnight at 50° C. in an oil bath and concentrated under vacuumand diluted by 10 ml of water. The pH value of the aqueous solution wasadjusted to 3-4 with 1N hydrogen chloride. The resulting solid wascollected by filtration and washed with methanol. This resulted in 54 mg(50%) of 3-(2-methylpiperidin-1-yl)-2-phenylquinoxaline-6-carboxylicacid as a yellow solid.

LC-MS: (ES, m/z): 348 [M+H]⁺

¹H-NMR (300 MHz, DMSO, ppm): δ 8.26 (s, 1H), 7.99-7.92 (m, 4H),7.57-7.51 (m, 3H), 4.07-4.05 (d, J=5.7 Hz, 1H), 3.10-3.03 (m, 1H),1.62-1.34 (m, 6H), 1.08-1.04 (t, J=6.6 Hz, 3H).

EXAMPLE 46 3-(Cyclopropyl(methyl)amino)-2-phenylquinoxaline-6-carboxylicacid

Step 1. Methyl 3-(cyclopropylamino)-2-phenylquinoxaline-6-carboxylate

Into a 20-mL sealed tube, was placed methyl3-chloro-2-phenylquinoxaline-6-carboxylate (200 mg, 0.67 mmol, 1.00equiv), cyclopropanamine (10 mL), DMSO (1 mL). The resulting solutionwas stirred overnight at 50° C. in an oil bath. The resulting mixturewas concentrated under vacuum. The resulting solution was diluted withH₂O. The resulting solids were collected by filtration and applied ontoa silica gel column with PE/EA (50:1). This resulted in 182.4 mg (83%)of methyl 3-(cyclopropylamino)-2-phenylquinoxaline-6-carboxylate as ayellow solid.

LC-MS: (ES, m/z): 320 [M+H]⁺

Step 2. 3-(Cyclopropyl(methyl)amino)-2-phenylquinoxaline-6-carboxylicacid

Into a 50-mL round-bottom flask purged and maintained with an inertatmosphere of nitrogen, was placed a solution of methyl3-(cyclopropylamino)-2-phenylquinoxaline-6-carboxylate (182.4 mg, 0.56mmol, 1.00 equiv, 98%) in tetrahydrofuran (17 mL). Sodium hydride (274.5mg, 11.44 mmol, 20.00 equiv) was added. The resulting solution wasstirred for 1 h at room temperature. This was followed by the dropwiseaddition of CH₃I (809.4 mg, 5.70 mmol, 10.00 equiv) with stirring at 0°C. The resulting solution was allowed to react, with stirring, overnightat room temperature. The resulting mixture was concentrated under vacuumand diluted with 10 ml of water. The pH value of the aqueous solutionwas adjusted to 3-4 with 1N hydrogen chloride. The resulting solid wascollected by filtration and washed with water and methanol. Thisresulted in 66.5 mg (36%) of3-(cyclopropyl(methyl)amino)-2-phenylquinoxaline-6-carboxylic acid as ayellow solid.

LC-MS: (ES, m/z): 320 [M+H]⁺

¹H-NMR (300 MHz, DMSO, ppm): δ 8.26 (s, 1H), 7.95 (s, 2H), 7.80-7.78 (d,J=6 Hz, 2H), 7.51-7.50 (d, J=6.9 Hz, 3H), 3.00 (s, 3H), 2.45 (s, 1H),0.43 (s, 4H).

EXAMPLE 47 3-(2-Methylpyrrolidin-1-yl)-2-phenylquinoxaline-6-carboxylicacid

Step 1. Methyl3-(2-methylpyrrolidin-1-yl)-2-phenylquinoxaline-6-carboxylate

Into a 8-mL sealed tube, was placed methyl3-bromo-2-phenylquinoxaline-6-carboxylate (150 mg, 0.44 mmol, 1.00equiv), 2-methylpyrrolidine (74.8 mg, 0.88 mmol, 2.00 equiv), potassiumcarbonate (181.6 mg, 1.32 mmol, 3.00 equiv), and N,N-dimethylformamide(4 mL). The resulting solution was stirred overnight at 100° C. in anoil bath. The reaction was t quenched by the addition of water and theresulting solution was extracted with 5×20 mL of dichloromethane and theorganic layers were combined and dried over anhydrous sodium sulfate andconcentrated in vacuo. The residue was purified by silica gelchromatography with ethyl acetate/petroleum ether (1:100). This resultedin 110.3 mg (72%) of methyl3-(2-methylpyrrolidin-1-yl)-2-phenylquinoxaline-6-carboxylate as yellowoil.

LC-MS: (ES, m/z): 348 [M+H]⁺

Step 2. 3-(2-methylpyrrolidin-1-yl)-2-phenylquinoxaline-6-carboxylicacid

Into a 50-mL round-bottom flask, was placed a solution of methyl3-(2-methylpyrrolidin-1-yl)-2-phenylquinoxaline-6-carboxylate (110 mg,0.32 mmol, 1.00 equiv) in methanol (20 mL). Then a solution of sodiumhydroxide (63.4 mg, 1.58 mmol, 5.00 equiv) in water (2.5 mL) was addeddropwise with stirring. The resulting solution was stirred for 8 h at50° C. in an oil bath. The resulting mixture was concentrated undervacuum and diluted with 10 ml of water. The pH value of the aqueoussolution was adjusted to 3-4 with 1N hydrogen chloride. The resultingsolid was collected by filtration and washed with hexane. This resultedin 40 mg (38%) of3-(2-methylpyrrolidin-1-yl)-2-phenylquinoxaline-6-carboxylic acid as ayellow solid.

LC-MS: (ES, m/z): 334 [M+H]⁺

¹H-NMR (300 MHz, DMSO, ppm): δ 8.25 (s, 1H), 7.91 (s, 2H), 7.74-7.72 (d,J=6 Hz, 2H), 7.54-7.51 (d, J=9 Hz, 3H), 4.24-4.22 (d, J=6 Hz, 1H),3.02-2.93 (m, 2H), 2.12 (s, 1H), 1.75 (s, 1H), 1.53 (s, 2H), 1.33-1.31(d, J=6 Hz, 3H).

EXAMPLE 48 3-(sec-Butyl(methyl)amino)-2-phenylquinoxaline-6-carboxylicacid

Step 1. Methyl 3-(sec-butylamino)-2-phenylquinoxaline-6-carboxylate

Into a 8-mL sealed tube, was placed methyl3-bromo-2-phenylquinoxaline-6-carboxylate (150 mg, 0.44 mmol, 1.00equiv), butan-2-amine (193 mg, 2.64 mmol, 6.00 equiv), potassiumcarbonate (181.6 mg, 1.32 mmol, 3.00 equiv), toluene (3 mL). Theresulting solution was stirred overnight at 100° C. in an oil bath. Theresulting solution was concentrated under vacuum. The residue wasapplied onto a silica gel column with ethyl acetate/petroleum ether(1:10). This resulted in 109 mg (crude) of methyl3-(sec-butylamino)-2-phenylquinoxaline-6-carboxylate as yellow oil.

LC-MS: (ES, m/z): 336 [M+H]⁺

Step 2. 3-(sec-Butyl(methyl)amino)-2-phenylquinoxaline-6-carboxylic acid

Into a 50-mL round-bottom flask, was placed a solution of methyl3-(sec-butylamino)-2-phenylquinoxaline-6-carboxylate (133.6 mg, 0.40mmol, 1.00 equiv) in tetrahydrofuran (12 mL), and sodium hydride (96 mg,4.00 mmol, 10.03 equiv). The resulting solution was stirred 1 h at roomtemperature. Then a solution of methyl iodide (284 mg, 2.00 mmol, 5.01equiv) in tetrahydrofuran (1 mL) was added dropwise with stirring. Theresulting solution was stirred overnight at room temperature. The pHvalue of the solution was adjusted to 3-4 with 1N hydrogen chloride. Theresulting solution was concentrated under vacuum. The residue waspurified by silica gel chromatography with dichloromethane/petroleumether (10:1). The crude product (130 mg) was purified by Prep-HPLC underthe following conditions (1#-Waters 2767-1): Column, SunFire Prep C18, 5um, 19*100 mm; mobile phase, water with 0.05% TFA and CH₃CN (60% CH₃CNup to 80% in 6 min, up to 100% in 1 min, down to 60% in 1 min);Detector, UV 220 254 nm. This resulted in 52 mg (39%) of3-(sec-butyl(methyl)amino)-2-phenylquinoxaline-6-carboxylic acid as ayellow solid.

LC-MS: (ES, m/z): 336 [M+H]⁺

¹H-NMR (300 MHz, DMSO, ppm): δ 8.26 (s, 1H), 7.94 (s, 2H), 7.81-7.78 (t,J=9 Hz, 2H), 7.57-7.51 (m, 3H), 3.99-3.92 (q, J=9 Hz, 1H), 2.67 (s, 3H),1.56-1.37 (m, 2H), 1.02-1.00 (d, J=4 Hz, 3H), 0.65-0.60 (t, J=6 Hz, 3H).

EXAMPLE 49(R)-3-(3-Hydroxypyrrolidin-1-yl)-2-phenylquinoxaline-6-carboxylic acid

Step 1. (R)-methyl3-(3-hydroxypyrrolidin-1-yl)-2-phenylquinoxaline-6-carboxylate

Into an 8-mL sealed tube, was placed methyl3-bromo-2-phenylquinoxaline-6-carboxylate (150 mg, 0.44 mmol, 1.00equiv), (R)-pyrrolidin-3-ol hydrochloride (212 mg, 1.72 mmol, 4.00equiv), potassium carbonate (200 mg, 1.55 mmol, 3.00 equiv), toluene (5mL), DMSO (1.7 mL). The resulting solution was stirred overnight at 100°C. in an oil bath. The reaction was then quenched by the addition of 20ml of water. The resulting solution was extracted with 5×10 mL ofdichloromethane and the organic layers combined and concentrated undervacuum. The residue was applied onto a silica gel column withdichloromethane/methanol (70:1). This resulted in 147.4 mg (95%) of(R)-methyl3-(3-hydroxypyrrolidin-1-yl)-2-phenylquinoxaline-6-carboxylate as ayellow solid.

LC-MS (ES, m/z): 350 [M+H]⁺

Step 2.(R)-3-(3-hydroxypyrrolidin-1-yl)-2-phenylquinoxaline-6-carboxylic acid

Into a 50-mL round-bottom flask, was placed a solution of (R)-methyl3-(3-hydroxypyrrolidin-1-yl)-2-phenylquinoxaline-6-carboxylate (147.4mg, 0.42 mmol, 1.00 equiv) in methanol (15 mL). This was followed by thedropwise addition of a solution of sodium hydroxide (84.5 mg, 2.11 mmol,5.00 equiv) in water (2 mL) with stirring. The resulting solution wasstirred overnight at 50° C. in an oil bath. The pH value of the solutionwas adjusted to 3-4 with 1N hydrogen chloride. The resulting mixture wasconcentrated under vacuum. The crude product (120 mg) was purified byPrep-HPLC with the following conditions (1#-Waters 2767-1): Column,SunFire Prep C18, 5 um, 19*100 mm; mobile phase, water with 0.05% TFAand CH₃CN (20% CH₃CN up to 50% in 6 min, up to 100% in 1 min, down to20% in 1 min); Detector, UV 220 254 nm. This resulted in 35 mg (24%) of(R)-3-(3-hydroxypyrrolidin-1-yl)-2-phenylquinoxaline-6-carboxylic acidas a yellow solid.

LC-MS: (ES, m/z): 336 [M+H]⁺

¹H-NMR (300 MHz, DMSO, ppm): δ 8.34 (s, 1H), 8.24-7.49 (m, 7H), 4.21 (s,1H), 3.53-3.27 (m, 3H), 3.00-2.96 (d, J=16 Hz, 1H), 1.89-1.52 (m, 2H).

EXAMPLE 50(S)-3-(3-Hydroxypyrrolidin-1-yl)-2-phenylquinoxaline-6-carboxylic acid

Step 1. (S)-Methyl3-(3-hydroxypyrrolidin-1-yl)-2-phenylquinoxaline-6-carboxylate

Into an 8-mL sealed tube, was placed methyl3-bromo-2-phenylquinoxaline-6-carboxylate (150 mg, 0.44 mmol, 1.00equiv), (S)-pyrrolidin-3-ol hydrochloride (163 mg, 1.32 mmol, 3.00equiv), DIEA (227 mg, 1.76 mmol, 4.00 equiv), toluene (4 mL), in DMSO (2ml). The resulting solution was stirred at 100° C. for 7 hrs. Then thereaction was quenched by the addition of water. The resulting solutionwas extracted with 5×15 mL of dichloromethane and the organic layerswere combined and concentrated in vacuo. The residue was purified bysilica gel chromatography with dichloromethane/methanol (70:1). Thisresulted in 176 mg (crude) of (S)-methyl3-(3-hydroxypyrrolidin-1-yl)-2-phenylquinoxaline-6-carboxylate as ayellow solid.

LC-MS: (ES, m/z): 350 [M+H]⁺

¹H-NMR (300 MHz, CDCl₃, ppm): δ 8.56 (s, 1H), 8.04-7.96 (m, 2H),7.75-7.73 (t, J=1.5 Hz, 2H), 7.54-7.46 (m, 3H), 4.50 (s, 1H), 4.00 (s,3H), 3.70-3.30 (m, 4H), 2.00 (s, 2H).

Step 2.(S)-3-(3-Hydroxypyrrolidin-1-yl)-2-phenylquinoxaline-6-carboxylic acid

Into a 50-mL round-bottom flask, was placed a solution of (S)-methyl3-(3-hydroxypyrrolidin-1-yl)-2-phenylquinoxaline-6-carboxylate (170 mg,0.49 mmol, 1.00 equiv) in methanol (20 mL). This was followed by thedropwise addition of a solution of sodium hydroxide (97.4 mg, 2.44 mmol,5.00 equiv) in water (2.5 mL) with stirring. The resulting solution wasstirred overnight at 50° C. in an oil bath. The pH value of the solutionwas adjusted to 3-4 with 1N hydrogen chloride. The resulting solid wascollected by filtration and washed with water and methanol. The solidwas dried in an oven. This resulted in 40 mg (25%) of(S)-3-(3-hydroxypyrrolidin-1-yl)-2-phenylquinoxaline-6-carboxylic acidas a yellow solid.

LC-MS: (ES, m/z): 336 [M+H]⁺

¹H-NMR (300 MHz, DMSO, ppm): δ 8.32-8.24 (d, J=24 Hz, 1H), 7.94-7.86 (m,2H), 7.70-7.68 (m, J=2.1 Hz, 2H), 7.54-7.52 (d, J=6 Hz, 3H), 4.89 (s,1H), 4.22 (s, 1H), 3.55-3.49 (m, 2H), 3.00-2.96 (d, J=12 Hz, 1H),1.89-1.79 (m, 2H).

EXAMPLE 51(R)-3-(2-(Methoxymethyl)pyrrolidin-1-yl)-2-phenylquinoxaline-6-carboxylicacid

Step 1. (S)-methyl3-(2-(methoxymethyl)pyrrolidin-1-yl)-2-phenylquinoxaline-6-carboxylate

Into a 10-mL pressure tank reactor, was placed(S)-2-(methoxymethyl)pyrrolidine (96.45 mg, 0.85 mmol, 5.00 equiv),methyl 3-chloro-2-phenylquinoxaline-6-carboxylate (50 mg, 0.17 mmol,1.00 equiv), potassium carbonate (46.7 mg, 0.34 mmol, 2.00 equiv),toluene/DMSO (2/0.4 mL). The resulting solution was stirred overnight at100° C. in an oil bath. The resulting mixture was concentrated undervacuum. The reaction was then quenched by the addition of 10 mL ofwater. The resulting solution was extracted with 3×30 mL of ethylacetate and the organic layers combined. The residue was applied onto asilica gel column with ethyl acetate/petroleum ether (1:50). Thisresulted in 17 mg (27%) of (S)-methyl3-(2-(methoxymethyl)pyrrolidin-1-yl)-2-phenylquinoxaline-6-carboxylateas a yellow solid.

LC-MS (ES, m/z): 378 [M+H]⁺

Step 2.(R)-3-(2-(methoxymethyl)pyrrolidin-1-yl)-2-phenylquinoxaline-6-carboxylicacid

Into a 50-mL round-bottom flask, was placed a solution of (R)-methyl3-(2-(methoxymethyl)pyrrolidin-1-yl)-2-phenylquinoxaline-6-carboxylate(66 mg, 0.18 mmol, 1.00 equiv) in methanol (15 mL). A solution of sodiumhydroxide (35 mg, 0.88 mmol, 5.00 equiv) in water (2 mL) was added. Theresulting solution was stirred for 2 hrs at 50° C. in an oil bath. Theresulting mixture was concentrated under vacuum and diluted in 20 mL ofwater. The pH value of the aqueous solution was adjusted to 4-5 withhydrogen chloride (1 mol/L). The resulting solids were collected byfiltration. The residue was applied onto a silica gel column withdichloromethane/methanol (10:1). This resulted in 25 mg (39%) of(R)-3-(2-(methoxymethyl)pyrrolidin-1-yl)-2-phenylquinoxaline-6-carboxylicacid as a yellow solid.

LC-MS (ES, m/z): 364 [M+H]⁺

¹H-NMR (300 MHz, DMSO, ppm): δ 13.12 (s, 1H), 8.243-8.239 (d, J=1.2 Hz,1H), 7.95-7.88 (m, 2H), 7.75-7.72 (m, 2H), 7.56-7.49 (m, 3H), 4.51-4.47(m, 1H), 3.70-3.65 (m, 1H), 3.52-3.47 (m, 1H), 3.32-3.30 (d, J=5.1 Hz1H), 2.96-2.93 (m, 2H), 2.06-2.03 (m, 1H), 1.82-1.74 (m, 2H), 1.58-1.55(m, 1H).

EXAMPLE 52(R)-3-(2-(Hydroxymethyl)pyrrolidin-1-yl)-2-phenylquinoxaline-6-carboxylic

Step 1. (R)-methyl3-(2-(hydroxymethyl)pyrrolidin-1-yl)-2-phenylquinoxaline-6-carboxylate

Into an 8-mL sealed tube, was placed a solution of methyl3-chloro-2-phenylquinoxaline-6-carboxylate (150 mg, 0.50 mmol, 1.00equiv), (R)-pyrrolidin-2-ylmethanol (150 mg, 1.49 mmol, 3.00 equiv), andpotassium carbonate (345 mg, 2.50 mmol, 5.00 equiv) in Tol/DMSO (2.5/0.5mL). The resulting mixture was stirred overnight at 100° C. The residuewas purified by silica gel chromatography with ethyl acetate/petroleumether (1:50). This resulted in 120 mg (63%) of (R)-methyl3-(2-(hydroxymethyl)pyrrolidin-1-yl)-2-phenylquinoxaline-6-carboxylateas a yellow solid.

LC-MS: (ES, m/z): 364 [M+H]⁺

¹H-NMR (300 MHz, DMSO, ppm): δ 8.26 (d, J=1.5 Hz, 1H), 7.97-7.87 (m,2H), 7.80-7.77 (dd, J=1.8, 7.6 Hz, 2H), 7.56-7.46 (m, 3H), 4.78-4.74 (t,J=5.7 Hz, 1H), 4.36-4.32 (t, J=4.5 Hz, 1H), 3.93 (s, 3H), 3.72-3.67 (q,J=5.4 Hz, 2H), 2.97-2.92 (m, 2H), 2.04-1.75 (m, 4H).

Step 2.(R)-3-(2-(hydroxymethyl)pyrrolidin-1-yl)-2-phenylquinoxaline-6-carboxylicacid

Into a 100-mL round-bottom flask, was placed a solution of (R)-methyl3-(2-(hydroxymethyl)pyrrolidin-1-yl)-2-phenylquinoxaline-6-carboxylate(120 mg, 0.33 mmol, 1.00 equiv) and sodium hydroxide (66 mg, 1.65 mmol,4.99 equiv) in methanol/H₂O (20/5 mL). The reaction was stirred for 5 hat 70° C. and concentrated to dryness. The residue was dissolved in 20mL H₂O and washed with 10 mL EtOAc. The pH of the aqueous layer wasadjusted to 7 with 1N HCl and extracted with DCM/MeOH (10/1, 20 mL×5).The organic layers were combined and dried over Na₂SO₄ and concentratedto dryness. This resulted in 80 mg (66%) of(R)-3-(2-(hydroxymethyl)pyrrolidin-1-yl)-2-phenylquinoxaline-6-carboxylicacid as a yellow solid.

LC-MS (ES, m/z): 350 [M+H]⁺

¹H-NMR (300 MHz, DMSO, ppm): δ 8.21 (s, 1H), 7.94-7.90 (d, J=8.1 Hz,1H), 7.82-7.76 (m, 3H), 7.53-7.45 (m, 3H), 4.35 (s, 1H), 3.69-3.67 (d,J=3.9 Hz, 2H), 3.00-2.89 (m, 2H), 2.02-1.97 (m, 1H), 1.91-1.74 (m, 2H),1.58-1.49 (m, 1H).

EXAMPLE 53(S)-3-(2-(Hydroxymethyl)pyrrolidin-1-yl)-2-phenylquinoxaline-6-carboxylicacid

Step 1. (S)-methyl3-(2-(hydroxymethyl)pyrrolidin-1-yl)-2-phenylquinoxaline-6-carboxylate

Into an 8-mL sealed tube, was placed a solution of methyl3-chloro-2-phenylquinoxaline-6-carboxylate (150 mg, 0.50 mmol, 1.00equiv), (S)-pyrrolidin-2-ylmethanol (150 mg, 1.49 mmol, 3.00 equiv),potassium carbonate (345 mg, 2.50 mmol, 5.00 equiv) in Tol/DMSO (2.5/0.5mL). The resulting mixture was stirred for overnight at 100° C. Theresidue was applied onto a silica gel column with ethylacetate/petroleum ether (1:50). This resulted in 104 mg (54%) of(S)-methyl3-(2-(hydroxymethyl)pyrrolidin-1-yl)-2-phenylquinoxaline-6-carboxylateas a yellow solid.

LC-MS: (ES, m/z): 364 [M+H]⁺

¹H-NMR (300 MHz, DMSO, ppm): δ 8.26 (d, J=1.5 Hz, 1H), 7.97-7.87 (m,2H), 7.80-7.77 (m, 2H), 7.55-7.47 (m, 3H), 4.78-4.73 (t, J=5.7 Hz, 1H),4.35-4.32 (d, J=4.5 Hz, 1H), 3.93 (s, 3H), 3.76-3.67 (m, 2H), 3.00-2.92(m, 2H), 1.99-1.49 (m, 4H).

Step 2.(S)-3-(2-(hydroxymethyl)pyrrolidin-1-yl)-2-phenylquinoxaline-6-carboxylicacid

Into a 100-mL round-bottom flask, was placed a solution of (S)-methyl3-(2-(hydroxymethyl)pyrrolidin-1-yl)-2-phenylquinoxaline-6-carboxylate(104 mg, 0.29 mmol, 1.00 equiv) and sodium hydroxide (57.3 mg, 1.43mmol, 5.00 equiv) in methanol/H₂O (20/5 mL). The reaction was stirredfor 5 h at 70° C., concentrated to dryness, dissolved in 20 mL of H₂Oand washed with 10 mL EtOAc. The aqueous layer was adjusted pH to 7 with1N HCl and extracted with DCM/MeOH (10/1, 20 mL×5). The organic layerwas combined, dried over Na₂SO₄, and concentrated in vacuo. Thisresulted 45 mg (43%) of(S)-3-(2-(hydroxymethyl)pyrrolidin-1-yl)-2-phenylquinoxaline-6-carboxylicacid as a yellow solid.

LC-MS: (ES, m/z): 350 [M+H]⁺

¹H-NMR (300 MHz, DMSO, ppm): δ 8.23 (d, J=0.6 Hz, 1H), 7.93-7.86 (m,2H), 7.80-7.77 (m, 2H), 7.55-7.48 (m, 3H), 4.75 (s, 1H), 4.34 (t, J=3Hz, 1H), 3.73-3.64 (m, 2H), 2.97-2.91 (m, 2H), 2.01-1.96 (m, 1H),1.89-1.75 (m, 2H), 1.58-1.53 (m, 1H).

EXAMPLE 54 3-(3-Methylmorpholino)-2-phenylquinoxaline-6-carboxylic acid

Step 1. (E)-2-(4-methoxybenzylideneamino)propan-1-ol

Into a 500-mL 3-necked round-bottom flask purged and maintained with aninert atmosphere of nitrogen, was placed 4-methoxybenzaldehyde (54.4 g,400.00 mmol, 1.00 equiv), 2-aminopropan-1-ol (30 g, 400.00 mmol, 1.00equiv), 4-methylbenzenesulfonic acid (3.84 g, 20.21 mmol, 0.05 equiv),toluene (300 mL). The resulting solution was heated to reflux forovernight in an oil bath. The resulting mixture was concentrated undervacuum. The resulting mixture was washed with 3×50 mL of hexane. Theresulting solids were collected by filtration. This resulted in 63 g(82%) of (E)-2-(4-methoxybenzylideneamino)propan-1-ol as a white solid.

¹H-NMR (300 MHz, CDCl₃, ppm): δ 8.289 (s, 1H), 7.713-7.666 (m, 2H),6.960-6.913 (m, 2H), 3.861 (s, 3H), 3.712-3.693 (d, J=5.7 Hz, 2H),3.522-3.460 (m, 1H), 1.255-1.240 (t, J=4.5 Hz, 3H).

Step 2. 2-(4-Methoxybenzylamino)propan-1-ol

Into a 250-mL 3-necked round-bottom flask, was placed a solution of(E)-2-(4-methoxybenzylideneamino)propan-1-ol (15 g, 77.72 mmol, 1.00equiv) in methanol (150 mL). This was followed by the addition of NaBH₄(5.88 g, 155.56 mmol, 2.00 equiv) in several batches at −10-0° C. Theresulting solution was stirred for 2 hs at −10-0° C. in an ice/saltbath. The resulting mixture was concentrated under vacuum and dilutedwith 200 mL of water. The resulting aqueous solution was extracted with3×100 mL of ethyl acetate and the organic layers was combined and driedover anhydrous magnesium sulfate, concentrated under vacuum. Thisresulted in 11.1 g (73%) of 2-(4-methoxybenzylamino)propan-1-ol as awhite solid.

LC-MS: (ES, m/z): 196 [M+H]⁺

¹H NMR (300 MHz, CDCl₃, ppm): δ 7.281-7.251 (d, J=6 Hz, 2H), 6.907-6.860(m, 2H), 3.817 (s, 3H), 3.722-3.592 (m, 2H), 3.323-3.264 (m, 1H),2.887-2.830 (m, 1H), 1.120-1.098 (d, J=6.6 Hz, 3H)

Step 3. N-(4-Methoxybenzyl)-2-bromo-N-(1-hydroxypropan-2-yl)acetamide

Into a 250-mL 3-necked round-bottom flask purged and maintained with aninert atmosphere of nitrogen, was placed a solution of2-(4-methoxybenzylamino)propan-1-ol (11 g, 56.41 mmol, 1.00 equiv) indichloromethane (100 mL). This was followed by the addition oftriethylamine (5.7 g, 56.44 mmol, 1.00 equiv). To this was added asolution of 2-bromoacetyl bromide (11.4 g, 56.44 mmol, 1.00 equiv) indichloromethane (50 mL) dropwise with stirring at −17˜−25° C. Theresulting solution was stirred for 1 h at −17˜−25° C. in a liquidnitrogen bath. The resulting mixture was washed with 3×100 mL of water.The organic layer was dried over anhydrous magnesium sulfate andconcentrated under vacuum. This resulted in 16 g (90%) ofN-(4-methoxybenzyl)-2-bromo-N-(1-hydroxypropan-2-yl)acetamide as yellowoil.

LC-MS: (ES, m/z): 316 [M+H]⁺

Step 4. 4-(4-Methoxybenzyl)-5-methylmorpholin-3-one

Into a 500-mL 3-necked round-bottom flask purged and maintained with aninert atmosphere of nitrogen, was placed a solution of sodium hydride(3.46 g, 100.92 mmol, 2.00 equiv, 70%) in tetrahydrofuran (200 mL). Thiswas followed by the dropwise addition of a solution ofN-(4-methoxybenzyl)-2-bromo-N-(1-hydroxypropan-2-yl)acetamide (16 g,50.47 mmol, 1.00 equiv) in tetrahydrofuran (100 mL) with stirring at 25°C. The resulting solution was stirred overnight at 25° C. in an oilbath. The reaction was then quenched by the addition of 200 g ofwater/ice. The resulting solution was extracted with 5×200 mL ofdichloromethane and the organic layers combined. The organic layers werewashed with 3×50 mL of H₂O. Dried over anhydrous magnesium sulfate andconcentrated under vacuum. This resulted in 11.9 g (crude) of4-(4-methoxybenzyl)-5-methylmorpholin-3-one as yellow oil.

LC-MS: (ES, m/z): 236 [M+H]⁺

Step 5. 4-(4-Methoxybenzyl)-3-methylmorpholine

Into a 250-mL 3-necked round-bottom flask purged and maintained with aninert atmosphere of nitrogen, was placed a solution of LiAlH₄ (3.83 g,100.79 mmol, 2.00 equiv) in tetrahydrofuran (100 mL). This was followedby the addition of a solution of4-(4-methoxybenzyl)-5-methylmorpholin-3-one (11.9 g, 50.42 mmol, 1.00equiv) in tetrahydrofuran (50 mL) dropwise with stirring at 0° C. Theresulting solution was heated to reflux for 1 h in an oil bath andcooled to room temperature. The resulting solution was diluted with 100mL of H₂O. The resulting solution was extracted with 3×200 mL of ethylacetate and the organic layers combined and dried over anhydrousmagnesium sulfate and concentrated under vacuum. The residue was appliedonto a silica gel column with ethyl acetate/petroleum ether (1:30). Thisresulted in 7 g (58%) of 4-(4-methoxybenzyl)-3-methylmorpholine asyellow oil.

LC-MS: (ES, m/z): 222 [M+H]⁺

Step 6. 3-Methylmorpholine

Into a 250-mL round-bottom flask purged and maintained with an inertatmosphere of nitrogen, was placed a solution of4-(4-methoxybenzyl)-3-methylmorpholine (7 g, 31.53 mmol, 1.00 equiv) inmethanol (70 mL). This was followed by the addition of Palladium carbon(10%) (2 g). Then H₂ (g) was introduced in. The resulting solution wasstirred for overnight at 50° C. in an oil bath. The solids were filteredout. The resulting solution was concentrated under vacuum. This resultedin 2.1 g (66%) of 3-methylmorpholine as yellow oil.

LC-MS: (ES, m/z): 102 [M+H]⁺

Step 7. Methyl 3-(3-methylmorpholino)-2-phenylquinoxaline-6-carboxylate

Into a 10-mL sealed tube, was placed methyl3-bromo-2-phenylquinoxaline-6-carboxylate (150 mg, 0.44 mmol, 1.00equiv), and 3-methylmorpholine (443 mg, 4.39 mmol, 10.00 equiv) in DMSO(1 mL). The resulting solution was stirred overnight at 100° C. in anoil bath. The resulting mixture was concentrated in vacuo. The residuewas applied onto a silica gel column with ethyl acetate/petroleum ether(1:50). This resulted in 46 mg (29%) of methyl3-(3-methylmorpholino)-2-phenylquinoxaline-6-carboxylate as a yellowsolid.

LC-MS: (ES, m/z): 364 [M+H]⁺

¹H-NMR (300 MHz, CDCl₃, ppm): δ 8.615-8.609 (d, J=1.8 Hz, 1H),8.158-7.984 (m, 4H), 7.574-7.502 (m, 3H), 4.053-3.403 (m, 10H),1.218-1.196 (d, J=6.6 Hz, 3H).

Step 8. 3-(3-Methylmorpholino)-2-phenylquinoxaline-6-carboxylic acid

Into a 50-mL round-bottom flask, was placed a solution of methyl3-(3-methylmorpholino)-2-phenylquinoxaline-6-carboxylate (45 mg, 0.12mmol, 1.00 equiv) in methanol (10 mL). Then a solution of sodiumhydroxide (25 mg, 0.62 mmol, 5.00 equiv) in water (2 mL) was added. Theresulting solution was stirred for 2 hrs at 50° C. in an oil bath. Theresulting mixture was concentrated in vacuo. The residue was diluted by20 mL of water. The pH value of the aqueous solution was adjusted to 4-5with aq. hydrogen chloride (1 mol/L). The resulting solids werecollected by filtration. This resulted in 40 mg (90%) of3-(3-methylmorpholino)-2-phenylquinoxaline-6-carboxylic acid as a yellowsolid.

LC-MS: (ES, m/z): 350 [M+H]⁺

¹H-NMR (300 MHz, DMSO, ppm): δ 13.257 (s, 1H), 8.310 (s, 1H),8.037-7.963 (m, 4H), 7.585-7.504 (m, 3H), 3.818-3.770 (m, 2H),3.732-3.437 (m, 3H), 3.312-3.171 (m, 2H), 1.074-1.096 (d, J=6.6 Hz, 3H).

EXAMPLE 55(S)-3-(2-Methylpyrrolidin-1-yl)-2-phenylquinoxaline-6-carboxylic acid

Step 1. (S)-methyl3-(2-methylpyrrolidin-1-yl)-2-phenylquinoxaline-6-carboxylate

Into a 20-mL sealed tube, was placed methyl3-bromo-2-phenylquinoxaline-6-carboxylate (500 mg, 1.67 mmol, 1.00equiv), 2-methylpyrrolidine (285 mg, 2.92 mmol, 2.00 equiv), potassiumcarbonate (693.8 mg, 4.01 mmol, 3.00 equiv), N,N-dimethylformamide (6mL). The resulting solution was stirred overnight at 100° C. in an oilbath. The reaction was then quenched by the addition of water. Theresulting solution was extracted with 12×20 mL of dichloromethane andthe organic layers combined and dried over anhydrous sodium sulfate andconcentrated under vacuum. The residue was applied onto a silica gelcolumn with ethyl acetate/petroleum ether (1:100). This resulted in590.7 mg (92%) of methyl3-(2-methylpyrrolidin-1-yl)-2-phenylquinoxaline-6-carboxylate as yellowoil. Then the isomer was sent for chiral-prep-HPLC to get the product of(S)-methyl 3-(2-methylpyrrolidin-1-yl)-2-phenylquinoxaline-6-carboxylate(193.6 mg).

LC-MS: (ES, m/z): 348 [M+H]⁺

¹H-NMR (300 MHz, CDCl₃, ppm): δ 8.26-8.25 (d, J=1.5 Hz, 1H), 7.96-7.87(m, 2H), 7.75-7.71 (m, 2H), 7.57-7.47 (m, 3H), 4.27-4.20 (m, 1H), 3.93(s, 3H), 3.01-2.93 (m, 2H), 2.11 (s, 1H), 1.76-1.75 (d, J=3 Hz, 1H),1.56-1.50 (m, 2H), 1.34-1.32 (d, J=6 Hz, 3H).

Step 2. (S)-3-(2-methylpyrrolidin-1-yl)-2-phenylquinoxaline-6-carboxylicacid

Into a 50-mL round-bottom flask, was placed a solution of (S)-methyl3-(2-methylpyrrolidin-1-yl)-2-phenylquinoxaline-6-carboxylate (193.6 mg,0.56 mmol, 1.00 equiv) in methanol (15 mL). A solution of sodiumhydroxide (111.6 mg, 2.79 mmol, 5.00 equiv) in water (1.5 mL) was added.The resulting solution was stirred overnight at 50° C. in an oil bathand concentrated to dryness. The residue was diluted by 10 mL of waterand adjusted to PH=3-4 with 1N hydrogen chloride. The resulting solidwas collected by filtration. This resulted in 130 mg (69%) of(S)-3-(2-methylpyrrolidin-1-yl)-2-phenylquinoxaline-6-carboxylic acid asa yellow solid.

LC-MS (ES, m/z): 334 [M+H]⁺

¹H-NMR (300 MHz, DMSO, ppm): δ 8.25 (s, 1H), 7.94-7.87 (m, 2H),7.75-7.73 (d, J=6 Hz, 2H), 7.56-7.49 (m, 3H), 4.27-4.21 (m, 1H),3.02-2.94 (m, 2H), 2.12 (s, 1H), 1.75 (s, 1H), 1.56-1.51 (m, 2H),1.34-1.32 (d, J=6 Hz, 3H).

EXAMPLE 56(S)-3-(2-Methylpyrrolidin-1-yl)-2-phenylquinoxaline-6-carboxylic acid

Step 1. (R)-methyl3-(2-methylpyrrolidin-1-yl)-2-phenylquinoxaline-6-carboxylate

Into a 20-mL sealed tube, was placed methyl3-bromo-2-phenylquinoxaline-6-carboxylate (500 mg, 1.67 mmol, 1.00equiv), 2-methylpyrrolidine (285 mg, 2.92 mmol, 2.00 equiv), potassiumcarbonate (693.8 mg, 4.01 mmol, 3.00 equiv), N,N-dimethylformamide (6mL). The resulting solution was stirred overnight at 100° C. in an oilbath. The reaction was then quenched by the addition of water. Theresulting aqueous solution was extracted with 12×20 mL ofdichloromethane and the organic layers combined and dried over anhydroussodium sulfate and concentrated under vacuum. The residue was appliedonto a silica gel column with ethyl acetate/petroleum ether (1:100).This resulted in 590.7 mg (92%) of methyl3-(2-methylpyrrolidin-1-yl)-2-phenylquinoxaline-6-carboxylate as yellowoil. Then the isomer was sent for chiral-prep-HPLC to get the product of(R)-methyl 3-(2-methylpyrrolidin-1-yl)-2-phenylquinoxaline-6-carboxylate(178 mg).

LC-MS: (ES, m/z): 348 [M+H]⁺

¹H-NMR (300 MHz, DMSO, ppm): δ 8.26-8.25 (d, J=3 Hz, 1H), 7.96-7.88 (m,2H), 7.74-7.71 (m, 2H), 7.55-7.47 (m, 3H), 4.22 (s, 1H), 3.92 (s, 3H),2.98 (m, 2H), 2.11 (s, 1H), 1.75 (s, 1H), 1.53 (m, 2H), 1.33-1.31 (d,J=6 Hz, 3H).

Step 2. (R)-3-(2-methylpyrrolidin-1-yl)-2-phenylquinoxaline-6-carboxylicacid

Into a 50-mL round-bottom flask, was placed a solution of (R)-methyl3-(2-methylpyrrolidin-1-yl)-2-phenylquinoxaline-6-carboxylate (178 mg,0.51 mmol, 1.00 equiv) in methanol (15 mL). A solution of sodiumhydroxide (102.6 mg, 2.56 mmol, 5.00 equiv) in water (1.5 mL) was added.The resulting solution was stirred overnight at 50° C. in an oil bathand concentrated to dryness. The residue and diluted by 10 ml of waterand pH value of the aqueous solution was adjusted to pH=3-4 with 1Nhydrogen chloride. The resulting solid was collected by filtration asproduct. This resulted in 130 mg (75%) of(R)-3-(2-methylpyrrolidin-1-yl)-2-phenylquinoxaline-6-carboxylic acid asa yellow solid.

LC-MS: (ES, m/z): 334 [M+H]⁺

¹H-NMR (300 MHz, DMSO, ppm): δ 8.25 (s, 1H), 7.94-7.87 (m, 2H),7.75-7.73 (d, J=6 Hz, 2H), 7.56-7.49 (m, 3H), 4.25-4.23 (d, J=6 Hz, 1H),3.02-2.94 (m, 2H), 2.12 (s, 1H), 1.75 (s, 1H), 1.54 (s, 2H), 1.34-1.32(d, J=6 Hz, 3H).

EXAMPLE 572-(4-Fluorophenyl)-3-(isopropyl(methyl)amino)quinoxaline-6-carboxylicacid

Step 1. Methyl2-(4-fluorophenyl)-3-(isopropyl(methyl)amino)quinoxaline-6-carboxylate

Into a 10-mL sealed tube, was placed methyl2-chloro-3-(isopropyl(methyl)amino)quinoxaline-6-carboxylate (40 mg,0.14 mmol, 1.00 equiv), 4-fluorophenylboronic acid (57.4 mg, 0.41 mmol,3.00 equiv), Pd(PPh₃)₄ (31.4 mg, 0.03 mmol, 0.20 equiv), K₃PO₄ (116 mg,0.55 mmol, 4.00 equiv), 1,4-dioxane (3 mL). The resulting solution wasstirred for overnight at 110° C. in an oil bath. The solids werefiltered out. The filtrate was concentrated under vacuum. The residuewas purified by prep-TLC with ethyl acetate/petroleum ether (1:8). Thisresulted in 42 mg (87%) of methyl2-(4-fluorophenyl)-3-(isopropyl(methyl)amino)quinoxaline-6-carboxylateas a yellow solid.

LC-MS: (ES, m/z): 354 [M+H]⁺

¹H-NMR (300 MHz, CDCl₃, ppm): δ 8.600-8.595 (d, J=1.5 Hz, 1H),8.094-7.903 (m, 4H), 7.281-7.180 (m, 2H), 4.295-4.251 (m, 1H), 4.006 (s,3H), 2.779 (s, 3H), 1.127-1.105 (d, J=6.6 Hz, 6H).

Step 2.2-(4-fluorophenyl)-3-(isopropyl(methyl)amino)quinoxaline-6-carboxylicacid

Into a 50-mL round-bottom flask, was placed a solution of methyl2-(4-fluorophenyl)-3-(isopropyl(methyl)amino)quinoxaline-6-carboxylate(40 mg, 0.11 mmol, 1.00 equiv) in methanol (10 mL). Then a solution ofsodium hydroxide (22.67 mg, 0.57 mmol, 5.00 equiv) in water (1 mL) wasadded. The resulting solution was stirred for 5 h at 50° C. in an oilbath. The resulting mixture was concentrated under vacuum. The reactionwas then quenched by the addition of 20 mL of water. The pH value of theaqueous solution was adjusted to 4-5 with aq. hydrogen chloride (1mol/L). The resulting solids were collected by filtration. This resultedin 30 mg (76%) of2-(4-fluorophenyl)-3-(isopropyl(methyl)amino)quinoxaline-6-carboxylicacid as a yellow solid.

LC-MS: (ES, m/z): 340 [M+H]⁺

¹H-NMR (300 MHz, DMSO, ppm): δ 13.192 (s, 1H), 8.264 (s, 1H),7.946-7.897 (m, 4H), 7.404-7.346 (m, 2H), 4.189-4.146 (m, 1H), 2.671 (s,3H), 1.053-1.032 (d, J=6.3 Hz, 6H).

EXAMPLE 583-(Isopropyl(methyl)amino)-2-(4-methoxyphenyl)quinoxaline-6-carboxylicacid

Step 1. Methyl3-(isopropyl(methyl)amino)-2-(4-methoxyphenyl)quinoxaline-6-carboxylate

Into a 10-mL sealed tube, was placed methyl2-chloro-3-(isopropyl(methyl)amino)quinoxaline-6-carboxylate (40 mg,0.14 mmol, 1.00 equiv), 4-methoxyphenylboronic acid (62.6 mg, 0.41 mmol,3.00 equiv), Pd(PPh₃)₄ (31.4 mg, 0.03 mmol, 0.20 equiv), K₃PO₄ (116 mg,0.55 mmol, 4.00 equiv), 1,4-dioxane (3 mL). The resulting solution wasstirred for overnight at 110° C. in an oil bath. The solids werefiltered out. The filtrate was concentrated under vacuum. The residuewas purified by prep-TLC with ethyl acetate/petroleum ether (1:8). Thisresulted in 40 mg (80%) of methyl3-(isopropyl(methyl)amino)-2-(4-methoxyphenyl)quinoxaline-6-carboxylateas a yellow solid.

LC-MS: (ES, m/z): 366 [M+H]⁺

Step 2.3-(isopropyl(methyl)amino)-2-(4-methoxyphenyl)quinoxaline-6-carboxylicacid

Into a 50-mL round-bottom flask, was placed a solution of methyl3-(isopropyl(methyl)amino)-2-(4-methoxyphenyl)quinoxaline-6-carboxylate(40 mg, 0.11 mmol, 1.00 equiv) in methanol (10 mL). Then a solution ofsodium hydroxide (21.9 mg, 0.55 mmol, 5.00 equiv) in water (1 mL) wasadded. The resulting solution was stirred for 5 hrs at 50° C. in an oilbath. The resulting mixture was concentrated under vacuum. The reactionwas then quenched by the addition of 20 mL of water. The pH value of theaqueous solution was adjusted to 4-5 with aq. 1N hydrogen chloride. Theresulting solids were collected by filtration. This resulted in 25 mg(65%) of3-(isopropyl(methyl)amino)-2-(4-methoxyphenyl)quinoxaline-6-carboxylicacid as a yellow solid.

LC-MS: (ES, m/z): 352 [M+H]⁺

¹H-NMR (300 MHz, DMSO, ppm): δ 13.141 (s, 1H), 8.243 (s, 1H),7.955-7.840 (m, 4H), 7.105-7.076 (d, J=8.7 Hz, 2H), 4.237-4.194 (m, 1H),3.842 (s, 3H), 2.683 (s, 3H), 1.059-1.037 (d, J=6.6 Hz, 6H).

EXAMPLE 59(R)-3-(Methyl(1-phenylethyl)amino)-2-phenylquinoxaline-6-carboxylic acid

Step 1. (R)-methyl2-phenyl-3-(1-phenylethylamino)quinoxaline-6-carboxylate

Into a 8-mL pressure tank reactor, was placed methyl3-bromo-2-phenylquinoxaline-6-carboxylate (150 mg, 0.44 mmol, 1.00equiv), (R)-1-phenylethanamine (4 mL). The resulting solution wasstirred overnight at 100° C. in an oil bath. The residue was appliedonto a silica gel column with ethyl acetate/petroleum ether (1:5). Thisresulted in 144 mg (81%) of (R)-methyl2-phenyl-3-(1-phenylethylamino)quinoxaline-6-carboxylate as a yellowsolid.

LC-MS: (ES, m/z): 384 [M+H]⁺

¹H-NMR (300 MHz, CDCl₃, ppm): δ 8.56 (s, 1H), 8.51 (s, 1H), 8.50-4.25(m, 12H), 5.60-5.59 (d, J=3 Hz, 2H), 4.00 (s, 3H), 1.62-1.60 (t, J=3 Hz,3H).

Step 2.(R)-3-(methyl(1-phenylethyl)amino)-2-phenylquinoxaline-6-carboxylic acid

Into a 50-mL round-bottom flask purged and maintained with an inertatmosphere of nitrogen, was placed a solution of (R)-methyl2-phenyl-3-(1-phenylethylamino)quinoxaline-6-carboxylate (141 mg, 0.37mmol, 1.00 equiv) in THF (20 mL), sodium hydride (294.5 mg, 7.36 mmol,20.00 equiv, 60%). The resulting solution was stirred for 1 h at roomtemperature in an ice/salt bath. This was followed by the addition of asolution of CH₃I (522.8 mg, 3.68 mmol, 10.00 equiv) in THF (1 mL)dropwise with stirring at 0° C. The resulting solution was stirredovernight at 20° C. The pH value of the solution was adjusted to 3-4with 1N aqueous hydrogen chloride. The resulting mixture wasconcentrated under vacuum. The residue was applied onto a silica gelcolumn with dichloromethane/methanol (10:1). This resulted in 57 mg(39%) of(R)-3-(methyl(1-phenylethyl)amino)-2-phenylquinoxaline-6-carboxylic acidas a yellow solid.

LC-MS: (ES, m/z): 384 [M+H]⁺

¹H-NMR (300 MHz, DMSO, ppm): δ 8.24 (s, 1H), 8.01-7.99 (d, J=3 Hz, 1H),7.91-7.83 (m, 3H), 7.54-7.47 (m, 3H), 7.36-7.22 (m, 5H), 5.45-5.42 (d,J=9 Hz, 1H), 2.50-2.46 (d, J=12 Hz, 3H), 1.48-1.46 (d, J=6 Hz, 3H).

EXAMPLE 60(S)-3-(Methyl(1-phenylethyl)amino)-2-phenylquinoxaline-6-carboxylic acid

Step 1. (S)-methyl2-phenyl-3-(1-phenylethylamino)quinoxaline-6-carboxylate

Into a 8-mL pressure tank reactor, was placed methyl3-bromo-2-phenylquinoxaline-6-carboxylate (150 mg, 0.44 mmol, 1.00equiv), (S)-1-phenylethanamine (4 mL). The resulting solution wasstirred overnight at 100° C. in an oil bath. The residue was appliedonto a silica gel column with ethyl acetate/petroleum ether (1:50). Thisresulted in 78 mg (46%) of (S)-methyl2-phenyl-3-(1-phenylethylamino)quinoxaline-6-carboxylate as a yellowoil.

LC-MS: (ES, m/z): 384 [M+H]⁺

¹H-NMR (300 MHz, CDCl₃, ppm): δ 8.43-8.42 (d, J=3 Hz, 1H), 8.02-7.92 (m,2H), 7.78-7.75 (m, 2H), 7.63-7.56 (m, 3H), 7.43-7.25 (m, 6H), 5.52-5.51(t, J=3 Hz, 2H), 4.00 (s, 3H), 1.62-1.56 (m, 4H).

Step 2.(S)-3-(methyl(1-phenylethyl)amino)-2-phenylquinoxaline-6-carboxylic acid

Into a 50-mL round-bottom flask purged and maintained with an inertatmosphere of nitrogen, was placed a solution of (S)-methyl2-phenyl-3-(1-phenylethylamino)quinoxaline-6-carboxylate (110 mg, 0.29mmol, 1.00 equiv) in THF (9 mL), sodium hydride (137.9 mg, 5.74 mmol,20.00 equiv, 60%). The resulting solution was stirred for 1 h at roomtemperature in an ice/salt bath. This was followed by the addition of asolution of CH₃I (407.8 mg, 2.87 mmol, 10.00 equiv) THF (1 mL) dropwisewith stirring at 0° C. The resulting solution was stirred for overnightat 20° C. in an ice/salt bath. The pH value of the solution was adjusted15 to 3-4 with 1N hydrogen chloride. The resulting mixture wasconcentrated under vacuum. The residue was applied onto a silica gelcolumn with dichloromethane/methanol (10:1). This resulted in 40 mg(36%) of(S)-3-(methyl(1-phenylethyl)amino)-2-phenylquinoxaline-6-carboxylic acidas a yellow solid.

LC-MS: (ES, m/z): 384 [M+H]⁺

¹H-NMR (300 MHz, DMSO, ppm): δ 8.26 (s, 1H), 8.02-7.95 (m, 2H),7.89-7.85 (m, 2H), 7.57-7.50 (m, 3H), 7.34-7.25 (m, 5H), 5.55-5.48 (m,1H), 2.51-2.48 (d, J=6 Hz, 3H), 1.51-1.49 (d, J=6 Hz, 3H).

EXAMPLE 61(R)-3-(sec-Butyl(methyl)amino)-2-phenylquinoxaline-6-carboxylic acid

Step 1. (R)-methyl 3-(sec-butylamino)-2-phenylquinoxaline-6-carboxylate

Into a 8-mL sealed tube, was placed methyl3-bromo-2-phenylquinoxaline-6-carboxylate (150 mg, 0.439 mmol, 1.00equiv), (S)-butan-2-amine (2 mL), DMSO (1 mL). The resulting solutionwas stirred overnight at 60° C. in an oil bath. The resulting mixturewas concentrated under vacuum and diluted with H₂O. The resulting solidswere collected by filtration. The residue was applied onto a silica gelcolumn with PE/EA (50:1). This resulted in 114 mg of (R)-methyl3-(sec-butylamino)-2-phenylquinoxaline-6-carboxylate as yellow oil.

LC-MS: (ES, m/z): 336 [M+H]⁺

¹H-NMR (300 MHz, CDCl₃, ppm): δ 8.49 (s, 1H), 8.01-7.95 (m, 2H),7.75-7.72 (m, 2H), 7.63-7.54 (m, 3H), 5.09-5.07 (d, J=6 Hz, 1H),4.40-4.31 (m, 1H), 4.00 (s, 3H), 1.66-1.57 (m, 2H), 1.26-1.24 (d, J=6Hz, 3H), 1.00-0.95 (t, J=7.2 Hz, 3H).

Step 2. (R)-3-(sec-butyl(methyl)amino)-2-phenylquinoxaline-6-carboxylicacid

Into a 50-mL round-bottom flask purged and maintained with an inertatmosphere of nitrogen, was placed a solution of (R)-methyl3-(sec-butylamino)-2-phenylquinoxaline-6-carboxylate (110 mg, 0.33 mmol,1.00 equiv) in tetrahydrofuran (9 mL). sodium hydride (132 mg, 3.3 mmol,10.00 equiv, 60%) was added. The resulting solution was stirred for 1 hat room temperature. This was followed by the dropwise addition of asolution of CH₃I (922.5 mg, 6.50 mmol, 20.00 equiv) in tetrahydrofuran(2 mL) with stirring at 0° C. The resulting solution was stirred forovernight at 20° C. The resulting mixture was concentrated under vacuumand diluted by 10 ml of H₂O. The pH value of the aqueous solution wasadjusted to 3-4 with 1N hydrogen chloride. The resulting solid wascollected by filtration. This resulted solid in 67 mg (59%) of(R)-3-(sec-butyl(methyl)amino)-2-phenylquinoxaline-6-carboxylic acid asa yellow solid.

LC-MS: (ES, m/z): 336 [M+H]⁺

¹H-NMR (300 MHz, DMSO, ppm): δ 8.26 (s, 1H), 7.94 (s, 2H), 7.82-7.80 (t,J=1.8 Hz, 2H), 7.59-7.49 (m, 3H), 3.99-3.92 (m, 1H), 2.68 (s, 3H),2.59-1.35 (m, 2H), 1.03-1.01 (d, J=6 Hz, 3H), 0.66-0.61 (t, J=6 Hz, 3H).

EXAMPLE 62 3-(1H-Indol-1-yl)-2-phenylquinoxaline-6-carboxylicacid

Step 1. Methyl 3-(1H-indol-1-yl)-2-phenylquinoxaline-6-carboxylate

Into a 10-mL sealed tube, was placed methyl3-(indolin-1-yl)-2-phenylquinoxaline-6-carboxylate (150 mg, 0.39 mmol,1.00 equiv), DDQ (447 mg, 1.97 mmol, 4.00 equiv), DMSO (3 mL). Theresulting solution was stirred for overnight at 30° C. in an oil bath.The resulting solution was diluted with 20 mL of H₂O. The resultingsolids were collected by filtration and applied onto a silica gel columnwith ethyl acetate/petroleum ether (1:50). This resulted in 30 mg (20%)of methyl 3-(1H-indol-1-yl)-2-phenylquinoxaline-6-carboxylate as ayellow solid.

LC-MS: (ES, m/z): 380 [M+H]⁺

Step 2. 3-(1H-Indol-1-yl)-2-phenylquinoxaline-6-carboxylic acid

Into a 50-mL round-bottom flask, was placed a solution of methyl3-(1H-indol-1-yl)-2-phenylquinoxaline-6-carboxylate (40 mg, 0.11 mmol,1.00 equiv) in methanol (10 mL). A solution of sodium hydroxide (21.1mg, 0.53 mmol, 5.00 equiv) in H₂O (2 mL) was added. The resultingsolution was stirred for 2 hrs at 50° C. in an oil bath. The resultingmixture was concentrated in vacuo. The resulting solution was dilutedwith 20 mL of H₂O. The pH value of the aqueous solution was adjusted to4-5 with aq. 1N hydrogen chloride. The resulting solids were collectedby filtration. The crude product (50 mL) was further purified byFlash-Prep-HPLC with the following conditions (IntelFlash-1): Column,silica gel; mobile phase, H₂O/CH₃CN=100:1 increasing to H₂O/CH₃CN=100:60within 40 min; Detector, UV 254 nm. This resulted in 15 mg (38%) of3-(1H-indol-1-yl)-2-phenylquinoxaline-6-carboxylic acid as a yellowsolid.

LC-MS: (ES, m/z): 366 [M+H]⁺

¹H-NMR (300 MHz, DMSO, ppm): δ 8.442-8.351 (m, 2H), 8.088-8.059 (m, 1H),7.658-7.599 (m, 2H), 7.429-7.272 (m, 8H), 7.176-7.102 (m, 2H),6.601-6.591 (d, J=3 Hz, 1H).

EXAMPLE 632-(3,4-Difluorophenyl)-3-(isopropyl(methyl)amino)quinoxaline-6-carboxylicacid

Step 1. Methyl2-(3,4-difluorophenyl)-3-(isopropyl(methyl)amino)quinoxaline-6-carboxylate

Into a 10-mL sealed tube, was placed methyl2-chloro-3-(isopropyl(methyl)amino)quinoxaline-6-carboxylate (150 mg,0.51 mmol, 1.00 equiv), 3,4-difluorophenylboronic acid (241 mg, 1.54mmol, 3.00 equiv), Pd(PPh₃)₄ (118 mg, 0.10 mmol, 0.20 equiv), K₃PO₄ (433mg, 2.05 mmol, 4.00 equiv), 1,4-dioxane (5 mL). The resulting solutionwas stirred for overnight at 100° C. in an oil bath. The resultingmixture was concentrated under vacuum. The residue was applied onto asilica gel column with ethyl acetate/petroleum ether (1:30). Thisresulted in 100 mg (53%) of methyl2-(3,4-difluorophenyl)-3-(isopropyl(methyl)amino)quinoxaline-6-carboxylateas a yellow solid.

LC-MS: (ES, m/z): 372 [M+H]⁺

Step 2.2-(3,4-Difluorophenyl)-3-(isopropyl(methyl)amino)quinoxaline-6-carboxylicacid

Into a 50-mL round-bottom flask, was placed a solution of methyl2-(3,4-difluorophenyl)-3-(isopropyl(methyl)amino)quinoxaline-6-carboxylate(90 mg, 0.24 mmol, 1.00 equiv) in methanol (15 mL). A solution of sodiumhydroxide (49 mg, 1.23 mmol, 5.05 equiv) in H₂O (2 mL) was added. Theresulting solution was stirred for 2 hrs at 50° C. in an oil bath. Theresulting mixture was concentrated under vacuum. The resulting solutionwas diluted with 20 mL of H₂O. The pH value of the solution was adjustedto 4-5 with aq. hydrogen chloride (1 mol/L). The resulting solids werecollected by filtration. The crude product (90 mg) was purified byPrep-HPLC with the following conditions (1#-Waters 2767-1): Column,SunFire Prep C18, 5 um, 19*150 mm; mobile phase, water with 0.05% TFAand CH₃CN (60% CH3CN up to 90% in 8 min, up to 100% in 1.5 min);Detector, UV 220 254 nm. This resulted in 25 mg (28%) of2-(3,4-difluorophenyl)-3-(isopropyl(methyl)amino)quinoxaline-6-carboxylicacid as a yellow solid.

LC-MS: (ES, m/z): 358 [M+H]⁺

¹H-NMR (300 MHz, DMSO, ppm): δ 13.194 (s, 1H), 8.266 (s, 1H),7.960-7.918 (m, 3H), 7.717-7.704 (d, J=3.9 Hz, 1H), 7.630-7.595 (m, 1H),4.173-4.129 (m, 1H), 2.677 (s, 3H), 1.064-1.042 (d, J=6.6 Hz, 6H).

EXAMPLE 642-(4-Chlorophenyl)-3-(isopropyl(methyl)amino)quinoxaline-6-carboxylicacid

Step 1. Methyl2-(4-chlorophenyl)-3-(isopropyl(methyl)amino)quinoxaline-6-carboxylate

Into a 10-mL sealed tube, was placed methyl2-chloro-3-(isopropyl(methyl)amino)quinoxaline-6-carboxylate (200 mg,0.68 mmol, 1.00 equiv), 4-chlorophenylboronic acid (162 mg, 1.03 mmol,3.00 equiv), Pd(PPh₃)₄ (157 mg, 0.14 mmol, 0.20 equiv), K₃PO₄ (578 mg,2.74 mmol, 4.00 equiv), 1,4-dioxane (5 mL). The resulting solution wasstirred for overnight at 100° C. in an oil bath. The resulting mixturewas concentrated under vacuum. The residue was applied onto a silica gelcolumn with ethyl acetate/petroleum ether (1:30). This resulted in 50 mg(20%) of methyl2-(4-chlorophenyl)-3-(isopropyl(methyl)amino)quinoxaline-6-carboxylateas a yellow solid.

LC-MS: (ES, m/z): 370 [M+H]⁺

Step 2.2-(4-Chlorophenyl)-3-(isopropyl(methyl)amino)quinoxaline-6-carboxylicacid

Into a 50-mL round-bottom flask, was placed a solution of methyl2-(4-chlorophenyl)-3-(isopropyl(methyl)amino)quinoxaline-6-carboxylate(98 mg, 0.27 mmol, 1.00 equiv) in methanol (15 mL), a solution of sodiumhydroxide (53 mg, 1.32 mmol, 5.00 equiv) in water (2 mL). The resultingsolution was stirred for 2 h at 50° C. in an oil bath. The resultingmixture was concentrated under vacuum. The resulting solution wasdiluted with 20 mL of water. The pH value of the aqueous solution wasadjusted to 4-5 with aq. hydrogen chloride (1 mol/L). The resultingsolids were collected by filtration. The crude product (80 mg) waspurified by Prep-HPLC with the following conditions (1#-Waters 2767-1):Column, SunFire Prep C18, 5 um, 19*150 mm; mobile phase, water with0.05% TFA and CH₃CN (60% CH₃CN up to 90% in 8 min, up to 100% in 1.5min); Detector, UV 220 254 nm. This resulted in 25 mg (25%) of2-(4-chlorophenyl)-3-(isopropyl(methyl)amino)quinoxaline-6-carboxylicacid as a yellow solid.

LC-MS: (ES, m/z): 356 [M+H]⁺

¹H NMR (300 MHz, DMSO, ppm): δ 8.265 (s, 1H), 7.953-7.950 (d, J=0.9 Hz,2H), 7.907-7.878 (m, 2H), 7.626-7.597 (m, 2H), 4.220-4.134 (m, 1H),2.671 (s, 3H), 1.062-1.040 (d, J=6.6 Hz, 6H).

EXAMPLE 65 (R)-2-Phenyl-3-(2-(trifluoromethyl)pyrrolidin-1-yl)quinoxaline-6-carboxylic acid

Step 1. (R)-methyl2-phenyl-3-(2-(trifluoromethyl)pyrrolidin-1-yl)quinoxaline-6-carboxylate

Into a 8-mL sealed tube, was placed methyl3-bromo-2-phenylquinoxaline-6-carboxylate (100 mg, 0.29 mmol, 1.00equiv), (R)-2-(trifluoromethyl)pyrrolidine (95 mg, 0.68 mmol, 2.36equiv), n-BuOH (1.5 mL). The resulting solution was stirred for 3 daysat 110° C. The resulting mixture was concentrated under vacuum. Theresidue was applied onto a silica gel column with ethylacetate/petroleum ether (1:10). This resulted in 30 mg (26%) of(R)-methyl2-phenyl-3-(2-(trifluoromethyl)pyrrolidin-1-yl)quinoxaline-6-carboxylateas a yellow solid.

LC-MS: (ES, m/z): 402 [M+H]⁺

Step 2.(R)-2-phenyl-3-(2-(trifluoromethyl)pyrrolidin-1-yl)quinoxaline-6-carboxylicacid

Into a 25-mL round-bottom flask, was placed (R)-methyl2-phenyl-3-(2-(trifluoromethyl)pyrrolidin-1-yl)quinoxaline-6-carboxylate(40 mg, 0.10 mmol, 1.00 equiv), sodium hydroxide (20 mg, 0.50 mmol, 5.00equiv), methanol (5 mL), water (1 mL). The resulting solution wasstirred for 5 hs at 50° C. in an oil bath. The resulting mixture wasconcentrated under vacuum. The residue was diluted in 5 mL of water. ThePH value was aqueous solution was adjusted to 4 with aq hydrochloricacid (1N). The resulting solids were collected by filtration. The crudeproduct (50 mg) was purified by Prep-HPLC with the following conditions(1#-Waters 2767-1): Column, SunFire Prep C18, 5 um, 19*150 mm; mobilephase, water with 0.05% TFA and CH₃CN (60% CH3CN up to 90% in 8 min, upto 100% in 1.5 min); Detector, UV 220 254 nm. This resulted in 12 mg(30%) of(R)-2-phenyl-3-(2-(trifluoromethyl)pyrrolidin-1-yl)quinoxaline-6-carboxylicacid as a yellow solid.

LC-MS: (ES, m/z): 388 [M+H]⁺

¹H-NMR (300 MHz, DMSO, ppm): δ 13.178 (s, 1H), 8.334 (s, 1H),8.034-8.031 (d, J=0.9 Hz, 2H), 7.804-7.777 (m, 2H), 7.612-7.507 (m, 3H),5.710-5.635 (m, 1H), 3.017-2.928 (m, 2H), 2.293-2.250 (m, 1H),2.018-1.950 (m, 1H), 1.837-1.800 (m, 1H), 1.712-1.658 (m, 1H).

EXAMPLE 663-(6-Methoxy-3,4-dihydroquinolin-1(2H)-yl)-2-phenylquinoxaline-6-carboxylicacid

Step 1. 1-Bromo-2-(bromomethyl)-4-methoxybenzene

Into a 1000-mL round-bottom flask, was placed a solution of1-bromo-4-methoxy-2-methylbenzene (20 g, 100.00 mmol, 1.00 equiv) inCCl₄ (200 mL). Then NBS (19.58 g, 110.00 mmol, 1.10 equiv) and BPO (1.21g, 5.00 mmol, 0.05 equiv) were added. The resulting solution was heatedto reflux for 7 hs in an oil bath. The resulting solids were filteredout. The filtrate was concentrated under vacuum and applied onto asilica gel column with ethyl acetate/petroleum ether (1:500). Thisresulted in 5.9 g (21%) of 1-bromo-2-(bromomethyl)-4-methoxybenzene as alight yellow solid.

Step 2. 3-(2-Bromo-5-methoxyphenyl)propanenitrile

Into a 100-mL 3-necked round-bottom flask purged and maintained with aninert atmosphere of nitrogen, was placed a solution of MeCN (6.2 g,151.22 mmol, 10.00 equiv) in tetrahydrofuran (20 mL). This was followedby the addition of n-BuLi (15.1 mL, 2.50 equiv, 2.5 M in hexane)dropwise with stirring at −78° C. The resulting solution was stirred for1 h at −78° C. in a liquid nitrogen bath. To this was added a solutionof 1-bromo-2-(bromomethyl)-4-methoxybenzene (4.2 g, 15.11 mmol, 1.00equiv) in tetrahydrofuran (10 mL) dropwise with stirring at −78° C. Theresulting solution was allowed to react, with stirring, for anadditional 1 h while the temperature was maintained at −78° C. in aliquid nitrogen bath. The reaction mixture was then quenched by theaddition of aqNH₄Cl and extracted by EA (100 ml*3). The organic layerswas concentrated and applied onto a silica gel column with PE/EA (10:1).This resulted in 2.29 g (63%) of3-(2-bromo-5-methoxyphenyl)propanenitrile as a yellow semi-solid.

¹H-NMR (300 MHz, CDCl₃, ppm): δ 7.43-7.40 (m, 1H), 6.84-6.83 (d, J=3 Hz,1H), 6.71-6.68 (m, 1H), 3.78-3.75 (d, J=9 Hz, 1H), 3.04-2.93 (m, 2H),2.67-2.62 (t, J=6 Hz, 2H).

Step 3. 3-(2-Bromo-5-methoxyphenyl)propan-1-amine

Into a 250-mL round-bottom flask, was placed a solution of3-(2-bromo-5-methoxyphenyl)propanenitrile (2.39 g, 10.00 mmol, 1.00equiv) in tetrahydrofuran (40 mL). This was followed by the addition ofBH₃ solution in tetrahydrofuran (30 mL, 3.00 equiv) dropwise withstirring at 0° C. The resulting solution was stirred for 6 hs at 20° C.in an oil bath. The reaction was then quenched by the addition of water.The resulting solution was concentrated under vacuum. The residue wasdiluted in water. The pH value of the aqueous solution was adjusted to8-9 with 1N sodium hydroxide. The resulting aqueous solution wasextracted with 10×50 mL of dichloromethane. The organic layers wascombined and dried over anhydrous sodium sulfate and concentrated undervacuum. This resulted in 2.23 g (crude) of3-(2-bromo-5-methoxyphenyl)propan-1-amine as yellow oil.

LC-MS: (ES, m/z): 244 [M+H]⁺

Step 4. Methyl3-(3-(2-bromo-5-methoxyphenyl)propylamino)-2-phenylquinoxaline-6-carboxylate

Into a 8-mL sealed tube, was placed methyl3-bromo-2-phenylquinoxaline-6-carboxylate (200 mg, 0.58 mmol, 1.00equiv), 3-(2-bromo-5-methoxyphenyl)propan-1-amine (1.14 g, 2.35 mmol,4.00 equiv, 50%), n-BuOH (3 mL). The resulting solution was stirredovernight at 100° C. in an oil bath. The resulting mixture wasconcentrated under vacuum. The residue was applied onto a silica gelcolumn with ethyl acetate/petroleum ether (1:50). This resulted in 245mg (83%) of methyl3-(3-(2-bromo-5-methoxyphenyl)propylamino)-2-phenylquinoxaline-6-carboxylateas a yellow semi-solid.

LC-MS: (ES, m/z): 506 [M+H]⁺

Step 5. Methyl3-(6-methoxy-3,4-dihydroquinolin-1(2H)-yl)-2-phenylquinoxaline-6-carboxylate

Into a 8-mL sealed tube, was placed methyl3-(3-(2-bromo-5-methoxyphenyl)propylamino)-2-phenylquinoxaline-6-carboxylate(245 mg, 0.49 mmol, 1.00 equiv), Pd₂(dba)₃ (44.6 mg, 0.05 mmol, 0.10equiv), BINAP (60.4 mg, 0.10 mmol, 0.20 equiv), Cs₂CO3 (479.2 mg, 1.47mmol, 3.03 equiv), dioxane (4 mL). The resulting solution was stirredovernight at 100° C. in an oil bath. The residue was applied onto asilica gel column with ethyl acetate/petroleum ether (1:70). Thisresulted in 118 mg (57%) of methyl3-(6-methoxy-3,4-dihydroquinolin-1(2H)-yl)-2-phenylquinoxaline-6-carboxylateas a yellow solid.

LC-MS: (ES, m/z): 426 [M+H]⁺

Step 6.3-(6-Methoxy-3,4-dihydroquinolin-1(2H)-yl)-2-phenylquinoxaline-6-carboxylicacid

Into a 50-mL round-bottom flask, was placed a solution of methyl3-(6-methoxy-3,4-dihydroquinolin-1(2H)-yl)-2-phenylquinoxaline-6-carboxylate (118 mg, 0.28 mmol, 1.00equiv) in methanol (15 mL). This was followed by the addition of asolution of sodium hydroxide (55.6 mg, 1.39 mmol, 5.00 equiv) in water(2 mL) dropwise with stirring. The resulting solution was stirredovernight at 50° C. in an oil bath. The resulting mixture wasconcentrated under vacuum. The resulting solution was diluted with ofH₂O. The pH value of the aqueous solution was adjusted to 3-4 with 1Nhydrogen chloride. The resulting solids were collected by filtration.The crude product (100 mg) was purified by Prep-HPLC with the followingconditions (1#-Waters 2767-1): Column, SunFire Prep C18, 19*150 mm 5 um;mobile phase, water with 0.05% TFA and CH₃CN (60% CH₃CN up to 75% in 8min, up to 100% in 1.5 min); Detector, UV 220 254 nm. This resulted in57 mg (40%) of 3-(6-methoxy-3,4-dihydroquinolin-1(2H)-yl)-2-phenylquinoxaline-6-carboxylic acid as a orange solid.

LC-MS: (ES, m/z): 412 [M+H]⁺

¹H-NMR (300 MHz, CDCl₃, ppm): δ 8.30 (s, 1H), 8.04 (d, J=0.6 Hz, 2H),7.71-7.68 (m, 2H), 7.29-7.27 (t, J=3 Hz, 3H), 6.64-6.59 (m, 2H),6.34-6.30 (t, J=3 Hz, 1H), 3.74-3.70 (t, J=6 Hz, 2H), 3.60 (s, 3H),2.72-2.67 (t, J=6 Hz, 2H), 1.96-1.92 (t, J=6 Hz, 2H).

EXAMPLE 67 3-(Indolin-1-yl)-2-phenylquinoxaline-6-carboxylic acid

Step 1. 2-(2-Bromophenyl)ethanamine

Into a 500-mL 3-necked round-bottom flask, was placed2-(2-bromophenyl)acetonitrile (9.8 g, 49.99 mmol, 1.00 equiv),tetrahydrofuran (50 mL). This was followed by the addition of BH₃solution (250 mL, 1N in tetrahydrofuran) dropwise with stirring at 0° C.The resulting solution was stirred overnight at room temperature. Thereaction was then quenched by the addition of 50 mL of water. Theresulting mixture was concentrated under vacuum. The resulting solutionwas diluted with 50 mL of H₂O. The pH value of the aqueous solution wasadjusted to 2 with aq. hydrogen chloride (5 N). The aqueous solution waswashed with 3×20 mL of EA and adjusted to pH to 11 with sodiumhydroxide. The resulting aqueous solution was extracted with 3×50 mL ofethyl acetate and the organic layers combined and concentrated undervacuum. This resulted in 5 g (50%) of 2-(2-bromophenyl)ethanamine asbrown oil.

LC-MS: (ES, m/z): 200 [M+H]⁺

Step 2. Methyl3-(2-bromophenethylamino)-2-phenylquinoxaline-6-carboxylate

Into a 10-mL sealed tube, was placed methyl3-chloro-2-phenylquinoxaline-6-carboxylate (150 mg, 0.50 mmol, 1.00equiv), 2-(2-bromophenyl)ethanamine (300.5 mg, 1.51 mmol, 3.00 equiv),potassium carbonate (347.3 mg, 2.52 mmol, 5.00 equiv), toluene/DMSO (5/1mL). The resulting solution was stirred for overnight at 100° C. in anoil bath. The resulting mixture was concentrated under vacuum andapplied onto a silica gel column with ethyl acetate/petroleum ether(1:50). This resulted in 110 mg (47%) of methyl3-(2-bromophenethylamino)-2-phenylquinoxaline-6-carboxylate as a yellowsolid.

LC-MS: (ES, m/z): 462 [M+H]⁺

¹H-NMR (300 MHz, CDCl₃, ppm): δ 8.508-8.503 (d, J=1.5 Hz, 1H),8.037-7.936 (m, 2H), 7.633-7.513 (m, 6H), 7.281-7.152 (m, 2H),7.140-7.083 (m, 1H), 5.312-5.278 (m, 1H), 3.912-3.848 (m, 2H),3.203-3.157 (t, J=6.9 Hz, 2H).

Step 3. Methyl 3-(indolin-1-yl)-2-phenylquinoxaline-6-carboxylate

Into a 10-mL sealed tube, was placed methyl3-(2-bromophenethylamino)-2-phenylquinoxaline-6-carboxylate (110 mg,0.24 mmol, 1.00 equiv), Pd₂(dba)₃ (22 mg, 0.02 mmol, 0.10 equiv), BINAP(59.37 mg, 0.10 mmol, 0.40 equiv), Cs₂CO₃ (233 mg, 0.71 mmol, 3.00equiv), 1,4-dioxane (5 mL). The resulting solution was stirred forovernight at 100° C. in an oil bath. The resulting solids were filteredout. The filtrate was concentrated under vacuum and applied onto asilica gel column with ethyl acetate/petroleum ether (1:50). Thisresulted in 90 mg (99%) of methyl3-(indolin-1-yl)-2-phenylquinoxaline-6-carboxylate as a orange solid.

LC-MS: (ES, m/z): 382 [M+H]⁺

¹H-NMR (300 MHz, CDCl₃, ppm): δ 8.654 (s, 1H), 8.194-8.119 (m, 2H),7.916-7.884 (m, 2H), 7.779-7.457 (m, 4H), 7.281-7.228 (m, 1H),7.136-7.085 (t, J=7.65 Hz, 1H), 6.960-6.912 (t, J=7.2 Hz, 1H), 4.020 (s,3H), 3.853-3.798 (t, J=8.25 Hz, 2H), 3.122-3.068 (t, J=8.1 Hz, 2H).

Step 4. 3-(Indolin-1-yl)-2-phenylquinoxaline-6-carboxylic acid

Into a 50-mL round-bottom flask, was placed a solution of methyl3-(indolin-1-yl)-2-phenylquinoxaline-6-carboxylate (90 mg, 0.24 mmol,1.00 equiv) in methanol (15 mL). Then a solution of sodium hydroxide(47.2 mg, 1.18 mmol, 5.00 equiv) in water (2 mL) was added. Theresulting solution was stirred for 2 hrs at 50° C. in an oil bath. Theresulting mixture was concentrated under vacuum. The residue was dilutedin 20 mL of water. The pH value of the aqueous solution was adjusted to4-5 with aqueous hydrogen chloride (1 mol/L). The resulting solids werecollected by filtration. This resulted in 80 mg (92%) of3-(indolin-1-yl)-2-phenylquinoxaline-6-carboxylic acid as an orangesolid.

LC-MS: (ES, m/z): 368 [M+H]⁺

¹H-NMR (300 MHz, DMSO, ppm): δ 8.362 (s, 1H), 8.127-7.983 (m, 2H),7.868-7.855 (d, J=3.9 Hz, 2H), 7.454 (s, 3H), 7.261-7.175 (m, 2H),7.010-6.961 (t, J=7.35 Hz, 1H), 6.849-6.801 (t, J=7.2 Hz, 1H),3.781-3.730 (t, J=7.65 Hz, 2H), 3.043-2.992 (t, J=7.65 Hz, 2H).

EXAMPLE 683-(2,3-Dihydrobenzo[b][1,4]oxazin-4-yl)-2-phenylquinoxaline-6-carboxylicacid

Step 1. 2-(2-Bromophenoxy)acetonitrile

Into a 50-mL round-bottom flask, was placed 2-bromophenol (5.1 g, 29.48mmol, 1.00 equiv), 2-bromoacetonitrile (5.3 g, 44.19 mmol, 1.50 equiv),potassium carbonate (8 g, 57.97 mmol, 2.00 equiv), N,N-dimethylformamide(20 mL). The resulting solution was stirred overnight at 60° C. in anoil bath. The resulting solution was diluted with 5×50 mL of EA. Theorganic layer was washed with 50 mL of H₂O. Organic layers werecollected and concentrated under vacuum. The residue was applied onto asilica gel column with ethyl acetate/petroleum ether (1:100). Thisresulted in 6 g (96%) of 2-(2-bromophenoxy)acetonitrile as a brownsolid.

LC-MS (ES, m/z): 212 [M+H]⁺

Step 2. 2-(2-Bromophenoxy)ethanamine

Into a 500-mL 3-necked round-bottom flask purged and maintained with aninert atmosphere of nitrogen, was placed a solution of2-(2-bromophenoxy)acetonitrile (5.63 g, 26.68 mmol, 1.00 equiv) intetrahydrofuran (20 mL). This was followed by the addition of BH₃ intetrahydrofuran (143 mL, 5.30 equiv) dropwise with stirring at 0° C. Theresulting solution was stirred overnight at 20° C. in an oil bath andquenched by the addition of water (10 ml). The resulting mixture wasconcentrated under vacuum and diluted with water. The pH value of theaqueous solution was adjusted to 10 with 1N sodium hydroxide andextracted with 6×50 mL of dichloromethane. The organic layers wascombined and concentrated under vacuum. This resulted in 5.67 g (crude)of 2-(2-bromophenoxy)ethanamine as pale brown oil.

LC-MS: (ES, m/z): 216 [M+H]⁺

Step 3. Methyl3-(2-(2-bromophenoxy)ethylamino)-2-phenylquinoxaline-6-carboxylate

Into a 8-mL pressure tank reactor, was placed methyl3-bromo-2-phenylquinoxaline-6-carboxylate (150 mg, 0.44 mmol, 1.00equiv), 2-(2-bromophenoxy)ethanamine (750 mg, 1.74 mmol, 3.98 equiv,50%), n-BuOH (2 mL). The resulting solution was stirred overnight at100° C. in an oil bath. The resulting mixture was concentrated undervacuum. The residue was applied onto a silica gel column with PE/EA(10:1). This resulted in 163.9 mg (crude) of methyl3-(2-(2-bromophenoxy)ethylamino)-2-phenylquinoxaline-6-carboxylate as ayellow solid.

Step 4. Methyl3-(2,3-dihydrobenzo[b][1,4]oxazin-4-yl)-2-phenylquinoxaline-6-carboxylate

Into a 20-mL sealed tube purged and maintained with an inert atmosphereof nitrogen, was placed methyl3-(2-(2-bromophenoxy)ethylamino)-2-phenylquinoxaline-6-carboxylate(363.9 mg, 0.76 mmol, 1.00 equiv), Pd₂(dba)₃ (70.2 mg, 0.08 mmol, 0.10equiv), BINAP (189.8 mg, 0.31 mmol, 0.40 equiv), Cs₂CO₃ (746.1 mg, 2.29mmol, 3.00 equiv), 1,4-dioxane (5 mL). The resulting solution wasstirred overnight at 100° C. in an oil bath and concentrated undervacuum. The residue was applied onto a silica gel column with ethylacetate/petroleum ether (1:50). This resulted in 166.8 mg (44%) ofmethyl3-(2,3-dihydrobenzo[b][1,4]oxazin-4-yl)-2-phenylquinoxaline-6-carboxylateas yellow oil.

LC-MS: (ES, m/z): 398 [M+H]⁺

Step 5.3-(2,3-Dihydrobenzo[b][1,4]oxazin-4-yl)-2-phenylquinoxaline-6-carboxylicacid

Into a 50-mL round-bottom flask, was placed a solution of methyl3-(2,3-dihydrobenzo[b][1,4]oxazin-4-yl)-2-phenylquinoxaline-6-carboxylate(166.8 mg, 0.34 mmol, 1.00 equiv, 80%) in methanol (15 mL). This wasfollowed by the addition of a solution of sodium hydroxide (84 mg, 2.10mmol, 5.00 equiv) in water (1.5 mL) dropwise with stirring. Theresulting solution was stirred overnight at 50° C. in an oil bath. ThepH value of the aqueous solution was adjusted to 3-4 with 1N aqueoushydrogen chloride and concentrated under vacuum. The crude product (100mg) was purified by Prep-HPLC with the following conditions (1#-Waters2767-2): Column, SunFire Prep C18, 5 um, 19*150 mm; mobile phase, waterwith 0.05% TFA and CH₃CN (20% CH₃CN up to 35% in 8 min, up to 70% in 8min, up to 100% in 1.5 min); Detector, uv 220&254 nm. This resulted in40 mg (31%) of3-(2,3-dihydrobenzo[b][1,4]oxazin-4-yl)-2-phenylquinoxaline-6-carboxylicacid as a orange solid.

LC-MS: (ES, m/z): 384 [M+H]⁺

¹H-NMR (300 MHz, DMSO, ppm): δ 13.21 (s, 1H), 8.34 (s, 1H), 8.16-8.09(m, 2H), 7.91-7.88 (m, 2H), 7.42-7.40 (t, J=6 Hz, 3H), 6.91-6.88 (d, J=9Hz, 1H), 6.77-6.73 (t, J=6 Hz, 2H), 6.59-6.53 (m, 1H), 4.29-4.28 (d, J=3Hz, 2H), 3.67 (s, 2H).

EXAMPLE 693-(Isopropyl(methyl)amino)-2-(3-methoxyphenyl)quinoxaline-6-carboxylicacid

Step 1. Methyl3-(isopropyl(methyl)amino)-2-(3-methoxyphenyl)quinoxaline-6-carboxylate

Into a 10-mL sealed tube, was placed methyl2-chloro-3-(isopropyl(methyl)amino)quinoxaline-6-carboxylate (120 mg,0.41 mmol, 1.00 equiv), 3-methoxyphenylboronic acid (188 mg, 1.23 mmol,3.00 equiv), Pd(PPh₃)₄ (94 mg, 0.08 mmol, 0.20 equiv), K₃PO₄ (346 mg,1.64 mmol, 4.00 equiv), 1,4-dioxane (4 mL). The resulting solution wasstirred for overnight at 100° C. in an oil bath. The resulting mixturewas concentrated under vacuum. The residue was applied onto a silica gelcolumn with ethyl acetate/petroleum ether (1:30). This resulted in 50 mg(33%) of methyl3-(isopropyl(methyl)amino)-2-(3-methoxyphenyl)quinoxaline-6-carboxylateas a yellow solid.

LC-MS: (ES, m/z): 366 [M+H]⁺

Step 2.3-(Isopropyl(methyl)amino)-2-(3-methoxyphenyl)quinoxaline-6-carboxylicacid

Into a 50-mL round-bottom flask, was placed methyl3-(isopropyl(methyl)amino)-2-(3-methoxyphenyl)quinoxaline-6-carboxylate(50 mg, 0.14 mmol, 1.00 equiv), methanol (10 mL), sodium hydroxide (27.4mg, 0.69 mmol, 5.00 equiv), water (2 mL). The resulting solution wasstirred for 2 hs at 50° C. in an oil bath. The resulting mixture wasconcentrated under vacuum. The resulting solution was diluted with 20 mLof H2O. The pH value of the aqueous solution was adjusted to 4-5 withhydrogen chloride (1 mol/L). The resulting solids were collected byfiltration. This resulted in 20 mg (41%) of3-(isopropyl(methyl)amino)-2-(3-methoxyphenyl)quinoxaline-6-carboxylicacid as a yellow solid.

LC-MS: (ES, m/z): 352 [M+H]⁺

¹H-NMR (300 MHz, DMSO, ppm): δ 8.250 (s, 1H), 7.931 (s, 2H), 7.382-7.250(m, 3H), 7.076 (s, 1H), 4.218 (s, 1H), 3.827 (s, 3H), 2.699 (s, 3H),1.030-1.048 (d, J=5.4 Hz, 6H).

EXAMPLE 702-(3-Fluorophenyl)-3-(isopropyl(methyl)amino)quinoxaline-6-carboxylicacid

Step 1. Methyl2-(3-fluorophenyl)-3-(isopropyl(methyl)amino)quinoxaline-6-carboxylate

Into a 10-mL sealed tube, was placed methyl2-chloro-3-(isopropyl(methyl)amino)quinoxaline-6-carboxylate (110 mg,0.38 mmol, 1.00 equiv), 3-fluorophenylboronic acid (157.4 mg, 1.12 mmol,3.00 equiv), Pd(PPh₃)₄ (86.5 mg, 0.07 mmol, 0.20 equiv), K₃PO₄ (318 mg,1.51 mmol, 4.00 equiv), 1,4-dioxane (4 mL). The resulting solution wasstirred for overnight at 100° C. in an oil bath. The resulting mixturewas concentrated under vacuum. The residue was applied onto a silica gelcolumn with ethyl acetate/petroleum ether (1:30). This resulted in 75 mg(57%) of methyl2-(3-fluorophenyl)-3-(isopropyl(methyl)amino)quinoxaline-6-carboxylateas a yellow solid.

LC-MS: (ES, m/z): 354 [M+H]⁺

Step 2.2-(3-Fluorophenyl)-3-(isopropyl(methyl)amino)quinoxaline-6-carboxylicacid

Into a 50-mL round-bottom flask, was placed methyl2-(3-fluorophenyl)-3-(isopropyl(methyl)amino)quinoxaline-6-carboxylate(75 mg, 0.21 mmol, 1.00 equiv), methanol (15 mL), sodium hydroxide (42mg, 1.05 mmol, 4.94 equiv), water (2 mL). The resulting solution wasstirred for 2 hs at 50° C. in an oil bath. The resulting mixture wasconcentrated under vacuum. The resulting solution was diluted with 20 mLof H₂O. The pH value of the aqueous solution was adjusted to 4-5 withaqueous hydrogen chloride (1 mol/L). The resulting solids were collectedby filtration. The crude product (70 mg) was purified by Prep-HPLC withthe following conditions (1#-Waters 2767-2): Column, SunFire Prep C18, 5um, 19*150 mm; mobile phase, water with 0.05% TFA and CH₃CN (50% CH₃CNup to 80% in 8 min, up to 100% in 1.5 min); Detector, uv 220&254 nm.This resulted in 20 mg (27%) of2-(3-fluorophenyl)-3-(isopropyl(methyl)amino)quinoxaline-6-carboxylicacid as a yellow solid.

LC-MS: (ES, m/z): 340 [M+H]⁺

¹H-NMR (300 MHz, DMSO, ppm): δ 8.266 (s, 1H), 7.984-7.924 (m, 2H),7.689-7.623 (m, 2H), 7.596-7.550 (m, 1H), 7.378-7.316 (m, 1H),4.216-4.130 (m, 1H), 2.676 (s, 3H), 1.053-1.031 (d, J=6.6 Hz, 6H).

EXAMPLE 712-(2-Fluorophenyl)-3-(isopropyl(methyl)amino)quinoxaline-6-carboxylicacid

Into a 10-mL round-bottom flask, was placed methyl 2-chloro-3-(isopropylmethyl) amino)quinoxaline carboxylate (80 mg, 0.27 mmol, 1.00 equiv),2-fluorophenylboronic acid (115 mg, 0.82 mmol, 3.00 equiv), Pd(PPh₃)₄(62.9 mg, 0.05 mmol, 0.20 equiv), 1,4-dioxane (3 mL), K₃PO₄ (231 mg,1.09 mmol, 4.00 equiv). The resulting solution was stirred for overnightat 100° C. in an oil bath. The resulting mixture was concentrated undervacuum. The resulting solution was diluted with 40 mL of DCM:MeOH=10:1.The solids were filtered out. The filtrate was concentrated in vacuo.The crude product (100 mg) was purified by Prep-HPLC with the followingconditions (1#-Waters 2767-1): Column, SunFire Prep C18, 19*150 mm 5 um;mobile phase, water with 0.05% TFA and CH₃CN (50% CH₃CN up to 80% in 8min, up to 100% in 1.5 min); Detector, UV 220&254 nm. This resulted in40 mg (43%) of2-(2-fluorophenyl)-3-(isopropyl(methyl)amino)quinoxaline-6-carboxylicacid as a yellow solid.

LC-MS: (ES, m/z): 340 [M+H]⁺

¹H-NMR (300 MHz, CDCl₃, ppm): δ 13.250 (s, 1H), 8.268 (s, 1H), 7.945 (s,1H), 7.776-7.731 (m, 1H), 7.602-7.538 (m, 1H), 7.424-7.342 (m, 2H),4.299-4.212 (m, 1H), 2.636 (s, 3H), 1.017-0.995 (d, J=6.6 Hz, 6H).

EXAMPLE 72 3-(Cyclopentyl(methyl)amino)-2-phenylquinoxaline-6-carboxylicacid

Step 1. Methyl 3-(cyclopentylamino)-2-phenylquinoxaline-6-carboxylate

Into an 8-mL sealed tube, was placed methyl3-bromo-2-phenylquinoxaline-6-carboxylate (200 mg, 0.58 mmol, 1.00equiv), cyclopentanamine (246.8 mg, 2.90 mmol, 5.00 equiv), and n-BuOH(2 mL). The resulting solution was stirred for 4 hrs at 100° C. in anoil bath. The resulting mixture was concentrated in vacuo. The residuewas purified by silica gel chromatography with ethyl acetate/petroleumether (1:50) resulting in 214.1 mg (crude) of methyl3-(cyclopentylamino)-2-phenylquinoxaline-6-carboxylate as a yellow oil.

LC-MS (ES, m/z): 348 [M+H]⁺

Step 2. Methyl3-(cyclopentyl(methyl)amino)-2-phenylquinoxaline-6-carboxylate

Into a 50-mL round-bottom flask purged and maintained with an inertatmosphere of nitrogen, was placed a solution of methyl3-(cyclopentylamino)-2-phenylquinoxaline-6-carboxylate (214.1 mg, 0.62mmol, 1.00 equiv) in tetrahydrofuran (10 mL). This was followed by theaddition of sodium hydride (246.8 mg, 6.17 mmol, 10.00 equiv, 60%)dropwise with stirring at 0° C. The resulting solution was stirred for 1h at room temperature. To this was added a solution of CH₃I (1.75 g,12.32 mmol, 20.00 equiv) in tetrahydrofuran (2 mL) dropwise withstirring at 0° C. The resulting solution was stirred overnight at roomtemperature. The reaction was then quenched by the addition of water.The resulting mixture was concentrated under vacuum. This resulted in200 mg (crude) of methyl3-(cyclopentyl(methyl)amino)-2-phenylquinoxaline-6-carboxylate as yellowoil.

LC-MS: (ES, m/z): 362 [M+H]⁺

Step 3. 3-(Cyclopentyl(methyl)amino)-2-phenylquinoxaline-6-carboxylicacid

Into a 50-mL round-bottom flask, was placed a solution of methyl3-(cyclopentyl(methyl)amino)-2-phenylquinoxaline-6-carboxylate (200 mg,0.55 mmol, 1.00 equiv) in methanol (15 mL). This was followed by theaddition of a solution of sodium hydroxide (110.8 mg, 2.77 mmol, 5.00equiv) in water (3 mL) dropwise with stirring. The resulting solutionwas stirred for 3 hs at 50° C. in an oil bath. The pH value of theaqueous solution was adjusted to 3-4 with 1N hydrogen chloride. Theresulting solids were collected by filtration and washed with ether.This resulted in 56 mg (29%) of3-(cyclopentyl(methyl)amino)-2-phenylquinoxaline-6-carboxylic acid as ayellow solid.

LC-MS: (ES, m/z): 348 [M+H]⁺

¹H-NMR (300 MHz, DMSO, ppm): δ 13.15-13.12 (t, J=3 Hz, 1H), 8.26 (s,1H), 7.94 (d, J=0.3 Hz, 2H), 7.85-7.83 (d, J=6 Hz, 2H), 7.56-7.48 (m,3H), 4.31-4.27 (t, J=6 Hz, 1H), 2.69 (s, 3H), 1.67-1.54 (m, 6H),1.40-1.38 (d, J=6 Hz, 2H).

EXAMPLE 733-(Isopropyl(methyl)amino)-2-(4-methoxyphenyl)quinoxaline-6-carboxylicacid

Step 1. Methyl3-(isopropyl(methyl)amino)-2-(2-methoxyphenyl)quinoxaline-6-carboxylate

Into a 10-mL sealed tube, was placed methyl2-chloro-3-(isopropyl(methyl)amino)quinoxaline-6-carboxylate (290 mg,0.99 mmol, 1.00 equiv), 2-methoxyphenylboronic acid (453.5 mg, 2.96mmol, 3.00 equiv), Pd(PPh₃)₄ (228 mg, 0.20 mmol, 0.20 equiv), K₃PO₄ (837mg, 3.97 mmol, 4.00 equiv), 1,4-dioxane (4 mL). The resulting solutionwas stirred for overnight at 100° C. in an oil bath. The resultingmixture was concentrated under vacuum and applied onto a silica gelcolumn with ethyl acetate/petroleum ether (1:40). This resulted in 100mg (28%) of methyl3-(isopropyl(methyl)amino)-2-(2-methoxyphenyl)quinoxaline-6-carboxylateas a yellow solid.

LC-MS: (ES, m/z): 366 [M+H]⁺

Step 2.3-(Isopropyl(methyl)amino)-2-(4-methoxyphenyl)quinoxaline-6-carboxylicacid

Into a 50-mL round-bottom flask, was placed methyl3-(isopropyl(methyl)amino)-2-(4-methoxyphenyl)quinoxaline-6-carboxylate(110 mg, 0.30 mmol, 1.00 equiv), methanol (15 mL), sodium hydroxide (60mg, 1.50 mmol, 5.00 equiv), and water (2 mL). The resulting solution wasstirred for 5 hr at 50° C. in an oil bath. The resulting mixture wasconcentrated in vacuo and diluted with 20 mL of water. The pH value ofthe aqueous solution was adjusted to 4-5 with aq. hydrogen chloride (1mol/L). The resulting solids were collected by filtration. This resultedin 50 mg (46%) of3-(isopropyl(methyl)amino)-2-(4-methoxyphenyl)quinoxaline-6-carboxylicacid as a yellow solid.

LC-MS: (ES, m/z): 352 [M+H]⁺

¹H-NMR (300 MHz, DMSO, ppm): δ 13.099 (s, 1H), 8.218 (s, 1H),7.882-7.879 (d, J=0.9 Hz, 2H), 7.532-7.447 (m, 2H), 7.161-7.090 (m, 2H),4.449-4.405 (m, 1H), 3.744 (s, 3H), 2.565 (s, 3H), 1.002-0.980 (d, J=6.6Hz, 6H).

EXAMPLE 74(S)-2-(4-Fluorophenyl)-3-(2-methylpyrrolidin-1-yl)quinoxaline-6-carboxylicacid

Step 1. Methyl4-(1-(4-fluorophenyl)-2-methoxy-2-oxoethylamino)-3-nitrobenzoate

Into a 250-mL round-bottom flask, was placed methyl4-fluoro-3-nitrobenzoate (15.4 g, 77.78 mmol, 1.00 equiv),N,N-dimethylformamide (100 mL), methyl 2-amino-2-(4-fluorophenyl)acetatehydrochloride (20.4 g, 93.15 mmol, 1.20 equiv), and DIEA (50.2 g, 389.15mmol, 5.00 equiv). The reaction was stirred overnight at 35° C. in anoil bath. The resulting solution was diluted with 500 ml of H₂O and theresulting solids were collected by filtration. This resulted in 15 g(53%) of methyl4-(1-(4-fluorophenyl)-2-methoxy-2-oxoethylamino)-3-nitrobenzoate as ayellow solid.

Step 2. Methyl2-(4-fluorophenyl)-3-oxo-1,2,3,4-tetrahydroquinoxaline-6-carboxylate

Into a 100-mL round-bottom flask, was placed methyl4-(1-(4-fluorophenyl)-2-methoxy-2-oxoethylamino)-3-nitrobenzoate (3.5 g,9.67 mmol, 1.00 equiv), methanol (50 mL), and palladium on carbon (10%)(500 mg). Hydrogen gas was introduced to the reaction and it. wasstirred overnight at 30° C. in an oil bath. Then the solids werefiltered off and the filtrate was concentrated in vacuo. This resultedin 2.6 g (90%) of methyl2-(4-fluorophenyl)-3-oxo-1,2,3,4-tetrahydroquinoxaline-6-carboxylate asa light yellow solid.

LC-MS: (ES, m/z): 301[M+H]⁺

Step 3. Methyl 3-chloro-2-(4-fluorophenyl)quinoxaline-6-carboxylate

Into a 100-mL round-bottom flask, was placed methyl2-(4-fluorophenyl)-3-oxo-1,2,3,4-tetrahydroquinoxaline-6-carboxylate(1.2 g, 4.00 mmol, 1.00 equiv), POCl₃ (12.2 g, 80.26 mmol, 20.00 equiv),N,N-dimethylbenzenamine (4.9 g, 40.50 mmol, 10.00 equiv). The resultingsolution was stirred for overnight at 110° C. in an oil bath. Theresulting mixture was concentrated under vacuum and diluted with 50 mLof water. The pH value of the aqueous solution was adjusted to 7 withsodium bicarbonate (4 mol/L). The resulting mixture was concentratedunder vacuum and purified by silica gel chromatography with ethylacetate/petroleum ether (1:40).

This resulted in 0.5 g (40%) of methyl3-chloro-2-(4-fluorophenyl)quinoxaline-6-carboxylate as a white solid.

LC-MS: (ES, m/z): 317 [M+H]⁺

¹H-NMR (300 MHz, CDCl₃, ppm): δ 8.785-8.779 (d, J=1.8 Hz, 1H),8.433-8.398 (m, 1H), 8.214-8.185 (d, J=8.7 Hz, 1H), 7.973-7.926 (m, 2H),7.265 (d, 1H), 4.052 (s, 3H).

Step 4. (S)-Butyl2-(4-fluorophenyl)-3-(2-methylpyrrolidin-1-yl)quinoxaline-6-carboxylate

Into a 10-mL sealed tube, was placed methyl3-chloro-2-(4-fluorophenyl)quinoxaline-6-carboxylate (150 mg, 0.47 mmol,1.00 equiv), (S)-2-methylpyrrolidine (403 mg, 4.74 mmol, 9.99 equiv),butan-1-ol (2 mL). The resulting solution was stirred overnight at 110°C. in an oil bath. The resulting mixture was concentrated under vacuum.This resulted in 150 mg (crude) of (S)-butyl2-(4-fluorophenyl)-3-(2-methylpyrrolidin-1-yl)quinoxaline-6-carboxylateas a yellow solid.

LC-MS: (ES, m/z): 408 [M+H]⁺

Step 5.(S)-2-(4-Fluorophenyl)-3-(2-methylpyrrolidin-1-yl)quinoxaline-6-carboxylicacid

Into a 10-mL sealed tube, was placed (S)-butyl2-(4-fluorophenyl)-3-(2-methylpyrrolidin-1-yl)quinoxaline-6-carboxylate(150 mg, 0.37 mmol, 1.00 equiv), methanol (15 mL), sodium hydroxide (74mg, 1.85 mmol, 5.02 equiv), water (2 mL). The resulting solution wasstirred for 2 hrs at 50° C. in an oil bath. The resulting mixture wasconcentrated under vacuum and diluted with 20 mL of H₂O. The pH value ofthe aqueous solution was adjusted to 4-5 with aq. hydrogen chloride (1mol/L). The resulting solids were collected by filtration. The crudeproduct (150 mg) was purified by Prep-HPLC with the following conditions(1#-Waters 2767-1): Column, SunFire Prep C18, 19*150 mm 5 um; mobilephase, water with 0.05% TFA and CH₃CN (60% CH₃CN up to 75% in 8 min, upto 100% in 1.5 min); Detector, UV 220 254 nm. This resulted in 60 mg(46%) of(S)-2-(4-fluorophenyl)-3-(2-methylpyrrolidin-1-yl)quinoxaline-6-carboxylicacid as a yellow solid.

LC-MS: (ES, m/z): 352 [M+H]⁺

¹H-NMR (300 MHz, DMSO, ppm): δ 13.161 (s, 1H), 8.243-8.240 (d, J=0.9 Hz,1H), 7.941-7.770 (m, 4H), 7.395-7.336 (t, J=8.85 Hz, 2H), 4.242-4.221(m, 1H), 3.018-2.936 (m, 2H), 2.126 (s, 1H), 1.767 (s, 1H), 1.336-1.316(d, J=6.0 Hz, 3H).

EXAMPLE 75 Butyl2-(4-fluorophenyl)-3-(piperidin-1-yl)quinoxaline-6-carboxylate

Step 1. Butyl2-(4-fluorophenyl)-3-(piperidin-1-yl)quinoxaline-6-carboxylate

Into a 10-mL sealed tube, was placed methyl3-chloro-2-(4-fluorophenyl)quinoxaline-6-carboxylate (150 mg, 0.47 mmol,1.00 equiv), piperidine (403 mg, 4.74 mmol, 10.00 equiv), butan-1-ol (2mL). The resulting solution was stirred for overnight at 110° C. in anoil bath. The resulting mixture was concentrated under vacuum. Thisresulted in 150 mg (crude) of butyl2-(4-fluorophenyl)-3-(piperidin-1-yl)quinoxaline-6-carboxylate as ayellow solid.

LC-MS (ES, m/z): 408 [M+H]⁺

Step 2. 2-(4-Fluorophenyl)-3-(piperidin-1-yl)quinoxaline-6-carboxylicacid

Into a 50-mL round-bottom flask, was placed butyl2-(4-fluorophenyl)-3-(piperidin-1-yl)quinoxaline-6-carboxylate (150 mg,0.37 mmol, 1.00 equiv), methanol (15 mL), sodium hydroxide (74 mg, 1.85mmol, 5.02 equiv), water (2 mL). The resulting solution was stirred for2 hs at 50° C. in an oil bath. The resulting mixture was concentratedunder vacuum and diluted with 20 mL of H₂O. The pH value of the aqueoussolution was adjusted to 4-5 with aq hydrogen chloride (1 mol/L). Theresulting solids were collected by filtration. The crude product (150mg) was purified by Prep-HPLC with the following conditions (GilsonPre-HPLC (Max. pressure: 8 MPa)): Column, SunFire Prep C18, 19*150 mm 5um; mobile phase, water with 0.05% TFA and CH₃CN (70% CH₃CN up to 77.5%in 6 min, up to 100% in 0.1 min, hold 100% in 1.9 min); Detector, UV 220NMnm. This resulted in 70 mg (52%) of2-(4-fluorophenyl)-3-(piperidin-1-yl)quinoxaline-6-carboxylic acid as ayellow solid.

LC-MS: (ES, m/z): 352 [M+H]⁺

¹H-NMR (300 MHz, DMSO, ppm) δ 13.206 (s, 1H), 8.275 (s, 1H), 8.085-7.943(m, 4H), 7.416-7.357 (t, J=5.9 Hz, 2H), 3.198 (s, 4H), 1.533 (s, 6H).

EXAMPLE 76 3-(Azepan-1-yl)-2-(4-fluorophenyl)quinoxaline-6-carboxylicacid

Step 1. Butyl3-(azepan-1-yl)-2-(4-fluorophenyl)quinoxaline-6-carboxylate

Into a 10-mL sealed tube, was placed methyl3-chloro-2-(4-fluorophenyl)quinoxaline-6-carboxylate (150 mg, 0.47 mmol,1.00 equiv), azepane (470 mg, 4.75 mmol, 10.00 equiv), butan-1-ol (2mL). The resulting solution was stirred for overnight at 110° C. in anoil bath. The resulting mixture was concentrated under vacuum. Thisresulted in 150 mg (crude) of butyl3-(azepan-1-yl)-2-(4-fluorophenyl)quinoxaline-6-carboxylate as a yellowsolid.

LC-MS (ES, m/z): 422 [M+H]⁺

Step 2. 3-(Azepan-1-yl)-2-(4-fluorophenyl)quinoxaline-6-carboxylic acid

Into a 50-mL round-bottom flask, was placed butyl3-(azepan-1-yl)-2-(4-fluorophenyl)quinoxaline-6-carboxylate (150 mg,0.36 mmol, 1.00 equiv), methanol (15 mL), sodium hydroxide (71 mg, 1.77mmol, 4.98 equiv), water (2 mL). The resulting solution was stirred for2 hrs at 50° C. in an oil bath. The resulting mixture was concentratedunder vacuum. The resulting solution was diluted with 20 mL of H₂O. ThepH value of the aqueous solution was adjusted to 4-5 with aq hydrogenchloride (1 mol/L). The resulting solids were collected by filtration.The crude product (150 mg) was purified by Prep-HPLC with the followingconditions (1#-Waters 2767-1): Column, XbridgePrep Shield RP 18, 5 um,19*150 mm; mobile phase, water with 0.05% TFA and CH₃CN (60% CH₃CN up to90% in 8 min, up to 100% in 1.5 min); Detector, UV 220 254 nm. Thisresulted in 80 mg (61%) of3-(azepan-1-yl)-2-(4-fluorophenyl)quinoxaline-6-carboxylic acid as ayellow solid.

LC-MS: (ES, m/z): 366 [M+H]⁺

¹H-NMR (300 MHz, DMSO, ppm): δ 13.188 (s, 1H), 8.225 (s, 1H),7.932-7.709 (m, 4H), 7.388-7.329 (t, J=8.85 Hz, 2H), 3.343-3.334 (m,4H), 1.630 (s, 4H), 1.415 (s, 4H).

EXAMPLE 772-(Benzo[d][1,3]dioxol-5-yl)-3-(isopropyl(methyl)amino)quinoxaline-6-carboxylicacid

Step 1. Methyl2-(benzo[d][1,3]dioxol-5-yl)-3-(isopropyl(methyl)amino)quinoxaline-6-carboxylate

Into a 10-mL sealed tube, was placed methyl2-chloro-3-(isopropyl(methyl)amino)quinoxaline-6-carboxylate (160 mg,0.55 mmol, 1.00 equiv), benzo[d][1,3]dioxol-5-ylboronic acid (271 mg,1.63 mmol, 3.00 equiv), PCy₃ (76 mg, 0.27 mmol, 0.40 equiv), Pd₂(dba)₃(130 mg, 0.14 mmol, 0.20 equiv), K₃PO₄ (462 mg, 2.18 mmol, 4.00 equiv),and 1,4-dioxane (3 mL). The resulting solution was stirred for overnightat 100° C. in an oil bath. The resulting mixture was concentrated undervacuum. The residue was applied onto a silica gel column with ethylacetate/petroleum ether (1:4). This resulted in 150 mg (72%) of methyl2-(benzo[d][1,3]dioxol-5-yl)-3-(isopropyl(methyl)amino)quinoxaline-6-carboxylateas a yellow solid.

LC-MS-PH: (ES, m/z): 380 [M+H]⁺

Step 2.2-(Benzo[d][1,3]dioxol-5-yl)-3-(isopropyl(methyl)amino)quinoxaline-6-carboxylicacid

Into a 50-mL round-bottom flask, was placed a solution of methyl2-(benzo[d][1,3]dioxol-5-yl)-3-(isopropyl(methyl)amino)quinoxaline-6-carboxylate(150 mg, 0.40 mmol, 1.00 equiv), methanol (15 mL), sodium hydroxide (79mg, 1.98 mmol, 4.99 equiv), and water (2 mL). The resulting solution wasstirred for 2 h at 50° C. in an oil bath. The resulting mixture wasconcentrated under vacuum. The resulting solution was diluted with 20 mLof H₂O. The pH value of the aqueous solution was adjusted to 4-5 withhydrogen chloride (1 mol/L). The resulting solids were collected byfiltration. This resulted in 60 mg (40%) of2-(benzo[d][1,3]dioxol-5-yl)-3-(isopropyl(methyl)amino)quinoxaline-6-carboxylicacid as a yellow solid.

LC-MS: (ES, m/z): 366 [M+H]⁺

¹H NMR (300 MHz, DMSO, ppm) δ 13.035 (s, 1H), 8.238 (s, 1H), 7.946-7.895(m, 2H), 7.412-7.388 (m, 2H), 7.075-7.055 (d, J=6.0 Hz, 1H), 6.123 (s,2H), 4.233-4.183 (m, 1H), 2.693 (s, 3H), 1.060-1.043 (d, J=5.1 Hz, 6H).

EXAMPLE 782-(4-Fluorophenyl)-3-(3-(methoxymethyl)piperidin-1-yl)quinoxaline-6-carboxylicacid

Step 1. Methyl2-(4-fluorophenyl)-3-(3-(methoxymethyl)piperidin-1-yl)quinoxaline-6-carboxylate

Into a 50-mL sealed tube, was placed a solution of3-(methoxymethyl)piperidine hydrochloride (170 mg, 1.03 mmol, 2.00equiv) in dichloromethane (7 mL), and sodium methoxide (128 mg, 2.37mmol, 5.00 equiv). The resulting solution was stirred for 3 h at roomtemperature. The solids were filtered out. The resulting mixture wasconcentrated under vacuum and was added into a 8-mL sealed tube withmethyl 3-chloro-2-(4-fluorophenyl)quinoxaline-6-carboxylate (150 mg,0.47 mmol, 1.00 equiv) and DMSO (4 mL). The mixture was stirredovernight at 100° C. Water was added to quench the reaction and theresulting solids were collected by filtration. The residue was purifiedby silica gel column chromatography with PE/EA (50:1). This resulted in179.9 mg (88%) of methyl2-(4-fluorophenyl)-3-(3-(methoxymethyl)piperidin-1-yl)quinoxaline-6-carboxylateas a yellow solid.

LC-MS: (ES, m/z): 410 [M+H]⁺

Step 2.2-(4-Fluorophenyl)-3-(3-(methoxymethyl)piperidin-1-yl)quinoxaline-6-carboxylicacid

Into a 50-mL round-bottom flask, was placed a solution of methyl2-(4-fluorophenyl)-3-(3-(methoxymethyl)piperidin-1-yl)quinoxaline-6-carboxylate(152.3 mg, 0.37 mmol, 1.00 equiv) in methanol (15 mL). This was followedby the addition of a solution of sodium hydroxide (44.7 mg, 1.12 mmol,3.00 equiv) in water (1.5 mL) dropwise with stirring. The resultingsolution was stirred for 4 h at 50° C. in an oil bath. The resultingmixture was concentrated under vacuum. The resulting solution wasdiluted with water. The pH value of the aqueous solution was adjusted to3-4 with 1N hydrogen chloride. The resulting solids were collected byfiltration and the crude product (240 mg) was purified by Prep-HPLCunder the following conditions (AGILENT Pre-HPLC (UV-Directed)): Column,SunFire Prep C18, 19*150 mm 5 um; mobile phase, water with 0.05% TFA andCH₃CN (45% CH₃CN up to 60% in 8 min, hold 60% in 5 min, up to 100% in0.1 min, hold 100% in 1.4 min); Detector, uv 220&254 nm. This resultedin 89 mg (61%) of2-(4-fluorophenyl)-3-(3-(methoxymethyl)piperidin-1-yl)quinoxaline-6-carboxylicacid as a yellow solid.

LC-MS: (ES, m/z): 396 [M+H]⁺

¹H-NMR (300 MHz, DMSO, ppm) 13.22 (s, 1H), 8.29-8.28 (d, J=3 Hz, 1H),8.05-7.95 (m, 4H), 7.41-7.35 (t, J=9H, 2H), 3.77-3.73 (d, J=12 Hz, 1H),3.59-3.55 (d, J=12 Hz, 1H), 3.19-3.07 (m, 5H), 2.77-2.70 (t, J=10.5 Hz,1H), 2.60-2.57 (d, J=9 Hz, 1H), 1.72 (s, 1H), 1.67-1.57 (m, 3H),1.50-1.49 (m, 1H).

EXAMPLE 793-(3,3-Dimethylpiperidin-1-yl)-2-(4-fluorophenyl)quinoxaline-6-carboxylicacid

Step 1. Methyl3-(3,3-dimethylpiperidin-1-yl)-2-(4-fluorophenyl)quinoxaline-6-carboxylate

Into a 10-mL sealed tube, was placed methyl3-chloro-2-(4-fluorophenyl)quinoxaline-6-carboxylate (150 mg, 0.47 mmol,1.00 equiv), 3,3-dimethylpiperidine (107 mg, 0.95 mmol, 2.00 equiv),DMSO (2 mL). The resulting solution was stirred overnight at 100° C. inan oil bath. The resulting solution was diluted with 20 mL of H₂O. Theresulting solids were collected by filtration. The residue was purifiedby silica gel column chromatography with ethyl acetate/petroleum ether(1:40). This resulted in 120 mg (64%) of methyl3-(3,3-dimethylpiperidin-1-yl)-2-(4-fluorophenyl)quinoxaline-6-carboxylateas a yellow solid.

LC-MS: (ES, m/z): 394 [M+H]⁺

Step 2.3-(3,3-Dimethylpiperidin-1-yl)-2-(4-fluorophenyl)quinoxaline-6-carboxylicacid

Into a 50-mL round-bottom flask, was placed a solution of methyl3-(3,3-dimethylpiperidin-1-yl)-2-(4-fluorophenyl)quinoxaline-6-carboxylate(120 mg, 0.31 mmol, 1.00 equiv), methanol (15 mL), sodium hydroxide (61mg, 1.52 mmol, 4.99 equiv), and water (2 mL). The resulting solution wasstirred for 2 h at 50° C. in an oil bath. The resulting mixture wasconcentrated under vacuum. The resulting solution was diluted with 20 mLof H₂O. The pH value of the aqueous solution was adjusted to 4-5 withhydrogen chloride (1 mol/L). The resulting solids were collected byfiltration. This resulted in 60 mg (52%) of3-(3,3-dimethylpiperidin-1-yl)-2-(4-fluorophenyl)quinoxaline-6-carboxylicacid as a yellow solid.

LC-MS: (ES, m/z): 380 [M+H]⁺

¹H-NMR (300 MHz, DMSO, ppm) δ 8.291-8.290 (d, J=0.3 Hz, 1H), 7.992-7.957(m, 4H), 7.435-7.391 (t, J=6.6 Hz, 2H), 3.067-3.039 (m, 4H), 1.466 (s,2H), 1.357-1.329 (m, 2H), 0.905 (s, 6H).

EXAMPLE 802-(4-Fluorophenyl)-3-(3-methylpiperidin-1-yl)quinoxaline-6-carboxylicacid

Into a 8-mL sealed tube, was placed methyl3-chloro-2-(4-fluorophenyl)quinoxaline-6-carboxylate (200 mg, 0.63 mmol,1.00 equiv), 3-methylpiperidine (313 mg, 3.16 mmol, 5.00 equiv), DMSO (3mL). The resulting solution was stirred for overnight at 110° C. in anoil bath. The reaction was then quenched by the addition of water. ThepH value of the aqueous solution was adjusted to 3-4 with 1N hydrogenchloride. The resulting solids were collected by filtration. The crudeproduct (240 mg) was purified by Prep-HPLC under the followingconditions (1#-UV1-SHIMADZU-SPD-20A): Column, SunFire Prep C18, 5 um,19*150 mm; mobile phase, water with 0.05% TFA and CH₃CN (30% CH₃CN up to100% in 8 min, hold 100% in 1.5 min, down to 30% in 1 min); Detector,Gilson UV Detector 220 nm. This resulted in 75 mg (32%) of2-(4-fluorophenyl)-3-(3-methylpiperidin-1-yl)quinoxaline-6-carboxylicacid as a yellow solid.

LC-MS: (ES, m/z): 366 [M+H]⁺

¹H NMR (300 MHz, DMSO, ppm) 13.24 (s, 1H), 8.28 (s, 1H), 8.05-7.94 (m,4H), 7.41-7.35 (t, J=9 Hz, 2H), 3.64-3.60 (d, J=12 Hz, 2H), 2.70-2.51(m, 1H), 2.50-2.37 (m, 1H), 1.75-1.46 (m, 5H), 1.06-1.05 (d, J=3 Hz,3H).

EXAMPLE 812-(2,3-Dihydrobenzo[b][1,4]dioxin-6-yl)-3-(isopropyl(methyl)amino)quinoxaline-6-carboxylicacid

Into a 10-mL sealed tube, was placed methyl2-chloro-3-(isopropyl(methyl)amino)quinoxaline-6-carboxylate (150 mg,0.51 mmol, 1.00 equiv), 2,3-dihydrobenzo[b][1,4]dioxin-6-ylboronic acid(184 mg, 1.02 mmol, 2.00 equiv), Pd(PPh₃)₂Cl₂ (36 mg, 0.05 mmol, 0.10equiv), K₃PO₄ (433 mg, 2.04 mmol, 3.99 equiv), 1,4-dioxane/H₂O (4/1 mL).The resulting solution was stirred overnight at 100° C. in an oil bath.The resulting mixture was concentrated under vacuum. The residue waspurified by silica gel column chromatography withdichloromethane/methanol (10:1). The crude product (70 mg) was purifiedby Prep-HPLC under the following conditions (1#-Waters 2767-1): Column,SunFire Prep C18, 19*150 mm 5 um; mobile phase, water with 0.05% TFA andCH₃CN (48% CH₃CN up to 68% in 8 min, up to 100% in 2 min); Detector, UV220 254 nm. This resulted in 20 mg (10%) of2-(2,3-dihydrobenzo[b][1,4]dioxin-6-yl)-3-(isopropyl(methyl)amino)quinoxaline-6-carboxylicacid as a yellow solid.

LC-MS: (ES, m/z): 380 [M+H]⁺

¹H NMR (300 MHz, DMSO, ppm) 813.109 (s, 1H), 8.233 (s, 1H), 7.949-7.885(m, 2H), 7.402-7.356 (m, 2H), 7.008-6.980 (d, J=8.4 Hz, 1H), 4.315 (s,4H), 4.251-4.163 (m, 1H), 2.729-2.693 (d, J=10.8 Hz, 3H), 1.061-1.039(d, J=6.6 Hz, 6H).

EXAMPLE 823-(Isopropyl(methyl)amino)-2-(4-(methylsulfonyl)phenyl)quinoxaline-6-carboxylicacid

Into a 10-mL round-bottom flask, was placed methyl2-chloro-3-(isopropyl(methyl) amino) quinoxaline-6-carboxylate (150 mg,0.51 mmol, 1.00 equiv), 4-(methylsulfonyl)phenylboronic acid (205 mg,1.02 mmol, 2.00 equiv), Pd(PPh₃)₄ (59 mg, 0.05 mmol, 0.10 equiv), K₃PO₄(433 mg, 2.04 mmol, 3.99 equiv), and 1,4-dioxane/H₂O (4/2 mL). Theresulting solution was stirred overnight at 100° C. in an oil bath. Theresulting mixture was concentrated under vacuum. The residue waspurified by silica gel column chromatography withdichloromethane/methanol (1:30). The crude product (60 mg) was purifiedby Prep-HPLC under the following conditions (1#-Waters 2767-2): Column,SunFire Prep C18, 19*150 mm 5 um; mobile phase, water with 0.05% TFA andCH₃CN (35% CH₃CN up to 57% in 9 min, up to 100% in 0.1 min, hold 100% in0.9 min); Detector, uV 220&254 nm. This resulted in 25 mg (12%) of3-(isopropyl(methyl)amino)-2-(4-(methylsulfonyl)phenyl)quinoxaline-6-carboxylicacid as a yellow solid.

LC-MS: (ES, m/z): 400 [M+H]⁺

¹H-NMR (300 MHz, DMSO, ppm) δ 13.198 (s, 1H), 8.280 (s, 1H), 8.091 (s,4H), 7.997-7.968 (d, J=8.7 Hz, 2H), 4.232-4.189 (m, 1H), 3.329-3.292 (d,J=11.1 Hz, 3H), 2.653 (s, 3H), 1.077-1.055 (d, J=6.6 Hz, 6H).

EXAMPLE 832-(Benzo[d][1,3]dioxol-5-yl)-3-((S)-2-methylpyrrolidin-1-yl)quinoxaline-6-carboxylicacid

Step 1. (S)-methyl1-benzyl-3-(2-methylpyrrolidin-1-yl)-2-oxo-1,2-dihydroquinoxaline-6-carboxylate

Into a 50-mL round-bottom flask, was placed methyl1-benzyl-3-chloro-2-oxo-1,2-dihydroquinoxaline-6-carboxylate (3 g, 9.15mmol, 1.00 equiv), (S)-2-methylpyrrolidine (1.55 g, 18.24 mmol, 2.00equiv), DMSO (16 mL). The resulting solution was stirred overnight at80° C. in an oil bath. The resulting solution was concentrated undervacuum. The residue was purified by silica gel column chromatographywith ethyl acetate/petroleum ether (1:20). This resulted in 2.2 g (64%)of (S)-methyl1-benzyl-3-(2-methylpyrrolidin-1-yl)-2-oxo-1,2-dihydroquinoxaline-6-carboxylateas a light yellow solid.

LC-MS: (ES, m/z): 378 [M+H]⁺

Step 2. (S)-methyl3-(2-methylpyrrolidin-1-yl)-2-oxo-1,2-dihydroquinoxaline-6-carboxylate

Into a 250-mL round-bottom flask, was placed a solution of (S)-methyl1-benzyl-3-(2-methylpyrrolidin-1-yl)-2-oxo-1,2-dihydroquinoxaline-6-carboxylate(2.2 g, 5.84 mmol, 1.00 equiv) in dichloromethane (100 mL). This wasfollowed by the addition of AlCl₃ (7.7 g, 58.33 mmol, 10.00 equiv) inseveral batches. The resulting solution was stirred overnight at 30° C.in an oil bath. The resulting solution was concentrated under vacuum.The residue was applied onto a silica gel column withdichloromethane/methanol (1:100). This resulted in 900 mg (53%) of(S)-methyl3-(2-methylpyrrolidin-1-yl)-2-oxo-1,2-dihydroquinoxaline-6-carboxylateas a brown solid.

LC-MS: (ES, m/z): 288 [M+H]⁺

Step 3. (S)-methyl2-chloro-3-(2-methylpyrrolidin-1-yl)quinoxaline-6-carboxylate

Into a 100-mL round-bottom flask, was placed a solution of (S)-methyl3-(2-methylpyrrolidin-1-yl)-2-oxo-1,2-dihydroquinoxaline-6-carboxylate(900 mg, 3.14 mmol, 1.00 equiv), toluene (20 mL), thionyl chloride (11.2g, 94.12 mmol, 30.00 equiv), N,N-dimethylformamide (4 mL). The resultingsolution was heated to reflux for 3 hr in an oil bath. The resultingmixture was concentrated under vacuum. The residue was purified bysilica gel column chromatography with ethyl acetate/petroleum ether(1:50). This resulted in 143 mg (13%) of (S)-methyl2-chloro-3-(2-methylpyrrolidin-1-yl)quinoxaline-6-carboxylate as yellowoil.

LC-MS: (ES, m/z): 306 [M+H]⁺

Step 4. Methyl2-(benzo[d][1,3]dioxol-5-yl)-3-((S)-2-methylpyrrolidin-1-yl)quinoxaline-6-carboxylate

Into a 8-mL sealed tube purged and maintained with an inert atmosphereof nitrogen, was placed (S)-methyl2-chloro-3-(2-methylpyrrolidin-1-yl)quinoxaline-6-carboxylate (89.2 mg,0.29 mmol, 1.00 equiv), benzo[d][1,3]dioxol-5-ylboronic acid (97.1 mg,0.58 mmol, 2.00 equiv), Pd(PPh₃)₄ (33.7 mg, 0.03 mmol, 0.10 equiv),K₃PO₄ (248 mg, 1.17 mmol, 4.00 equiv), dioxane (4 mL). The resultingsolution was stirred overnight at 100° C. in an oil bath. The resultingsolution was concentrated under vacuum. The residue was purified bysilica gel column chromatography with PE/EA (50:1). This resulted in 94mg (82%) of methyl2-(benzo[d][1,3]dioxol-5-yl)-3-((S)-2-methylpyrrolidin-1-yl)quinoxaline-6-carboxylateas yellow oil.

LC-MS: (ES, m/z): 392 [M+H]⁺

Step 5.2-(benzo[d][1,3]dioxol-5-yl)-3-((S)-2-methylpyrrolidin-1-yl)quinoxaline-6-carboxylicacid

Into a 50-mL round-bottom flask, was placed a solution of methyl2-(benzo[d][1,3]dioxol-5-yl)-3-((S)-2-methylpyrrolidin-1-yl)quinoxaline-6-carboxylate(94 mg, 0.24 mmol, 1.00 equiv) in methanol (15 mL). This was followed bythe addition of a solution of sodium hydroxide (58.9 mg, 1.47 mmol, 5.00equiv) in water (3 mL) dropwise with stirring. The resulting solutionwas stirred for 5 hr at 50° C. in an oil bath. The resulting mixture wasconcentrated under vacuum. The resulting solution was diluted with H₂O.The pH value of the aqueous solution was adjusted to 3-4 with 1N aqueoushydrogen chloride. The resulting solids were collected by filtration.The crude product (100 mg) was purified by Prep-HPLC with the followingconditions (1#-Waters 2767-2): Column, SunFire Prep C18, 19*150 mm 5 um;mobile phase, water with 0.05% TFA and CH₃CN (10% CH₃CN up to 80% in 8.5min, hold 80% in 1 min, up to 100% in 0.1 min, hold 100% in 0.8 min);Detector, UV 220&254 nm. This resulted in 40 mg (44%) of2-(benzo[d][1,3]dioxol-5-yl)-3-((S)-2-methylpyrrolidin-1-yl)quinoxaline-6-carboxylicacid as a yellow solid.

LC-MS: (ES, m/z): 378 [M+H]⁺

¹H NMR (400 MHz, DMSO, ppm) 13.05 (s, 1H), 8.23 (s, 1H), 7.91-7.90 (t,J=2 Hz, 2H), 7.30-7.23 (t, J=14 Hz, 2H), 7.07-7.05 (d, J=8 Hz, 1H),6.13-6.12 (d, J=4 Hz, 2H), 4.27-4.22 (m, 1H), 3.16-3.10 (m, 1H),3.02-2.98 (m, 1H), 2.13 (s, 1H), 1.79 (s, 1H), 1.62-1.50 (m, 2H),1.33-1.24 (m, 3H).

EXAMPLE 842-(1H-Indol-5-yl)-3-(isopropyl(methyl)amino)quinoxaline-6-carboxylicacid

Into a 10-mL sealed tube, was placed methyl2-chloro-3-(isopropyl(methyl)amino)quinoxaline-6-carboxylate (60 mg,0.20 mmol, 1.00 equiv), 1H-indol-5-ylboronic acid (100 mg, 0.62 mmol,3.05 equiv), Pd(PPh₃)₄ (23.6 mg, 0.02 mmol, 0.10 equiv), K₃PO₄ (174 mg,0.82 mmol, 4.01 equiv), 1,4-dioxane/H2O (4/1 mL). The resulting solutionwas stirred for overnight at 100° C. in an oil bath. The resultingmixture was concentrated under vacuum. The residue was applied onto asilica gel column with dichloromethane/methanol (10:1). The crudeproduct (60 mg) was purified by Prep-HPLC with the following conditions(1#-Waters 2767-2): Column, SunFire Prep C18, 19*150 mm 5 um; mobilephase, water with 0.05% TFA and CH₃CN (30% CH₃CN up to 55% in 8 min,hold 55% in 3 min, up to 100% in 0.1 min, hold 100% in 0.9 min);Detector, UV 220&254 nm. This resulted in 25 mg (33%) of2-(1H-indol-5-yl)-3-(isopropyl(methyl)amino)quinoxaline-6-carboxylicacid as a red solid.

LC-MS: (ES, m/z): 361 [M+H]⁺

¹H-NMR (300 MHz, DMSO, ppm) δ 11.305 (s, 1H), 8.254 (s, 1H), 8.124 (s,1H), 7.923-7.920 (d, J=0.9 Hz, 2H), 7.668-7.662 (m, 1H), 7.530-7.501 (d,J=8.7 Hz, 1H), 7.439-7.421 (t, J=2.7 Hz, 1H), 6.559 (s, 1H), 4.263-4.175(m, 1H), 2.704 (s, 3H), 1.013-0.990 (d, J=6.9 Hz, 6H).

EXAMPLE 853-(Isopropyl(methyl)amino)-2-(4-(trifluoromethoxy)phenyl)quinoxaline-6-carboxylicacid

Step 1. Methyl3-(isopropyl(methyl)amino)-2-(4-(trifluoromethoxy)phenyl)quinoxaline-6-carboxylate

Into a 10-mL sealed tube, was placed methyl2-chloro-3-(isopropyl(methyl)amino)quinoxaline-6-carboxylate (200 mg,0.68 mmol, 1.00 equiv), 4-(trifluoromethoxy)phenylboronic acid (280 mg,1.36 mmol, 1.99 equiv), Pd(PPh₃)₄ (157 mg, 0.14 mmol, 0.20 equiv), K₃PO₄(577 mg, 2.73 mmol, 4.01 equiv), 1,4-dioxane (4 mL). The resultingsolution was stirred for overnight at 100° C. in an oil bath. Theresulting mixture was concentrated under vacuum. The residue waspurified by silica gel column chromatography with ethylacetate/petroleum ether (1:40). This resulted in 120 mg (42%) of methyl3-(isopropyl(methyl)amino)-2-(4-(trifluoromethoxy)phenyl)quinoxaline-6-carboxylateas a yellow solid.

Step 2.3-(isopropyl(methyl)amino)-2-(4-(trifluoromethoxy)phenyl)quinoxaline-6-carboxylicacid

Into a 50-mL round-bottom flask, was placed a solution of methyl3-(isopropyl(methyl)amino)-2-(4-(trifluoromethoxy)phenyl)quinoxaline-6-carboxylate(120 mg, 0.29 mmol, 1.00 equiv) in methanol (15 mL), sodium hydroxide(57 mg, 1.43 mmol, 4.98 equiv), H₂O (2 mL). The resulting solution wasstirred for 2 hr at 50° C. in an oil bath. The resulting mixture wasconcentrated under vacuum and diluted with 20 mL of H₂O. The pH value ofthe aqueous solution was adjusted to 4-5 with hydrogen chloride (2.5mol/L). The resulting solids were collected by filtration. The crudeproduct (100 mg) was purified by Prep-HPLC with the following conditions(1#-Waters 2767-1): Column, SunFire Prep C18, 19*150 mm 5 um; mobilephase, water with 0.05% TFA and CH₃CN (65% CH₃CN up to 85% in 8 min, upto 100% in 2 min); Detector, UV 220 254 nm. This resulted in 70 mg (60%)of3-(isopropyl(methyl)amino)-2-(4-(trifluoromethoxy)phenyl)quinoxaline-6-carboxylicacid as a yellow solid.

LC-MS: (ES, m/z): 406 [M+H]⁺

¹H NMR (300 MHz, DMSO, ppm) δ 8.273 (s, 1H), 8.033-7.955 (m, 4H),7.552-7.525 (d, J=8.1 Hz, 2H), 4.202-4.114 (m, 1H), 2.667 (s, 3H),1.052-1.030 (d, J=6.6 Hz, 6H).

EXAMPLE 862-(4-Cyanophenyl)-3-(isopropyl(methyl)amino)quinoxaline-6-carboxylicacid

Into a 10-mL sealed tube, was placed methyl2-chloro-3-(isopropyl(methyl)amino)quinoxaline-6-carboxylate (150 mg,0.51 mmol, 1.00 equiv), 4-cyanophenylboronic acid (150 mg, 1.02 mmol,1.99 equiv), Pd(PPh₃)₂Cl₂ (36 mg, 0.05 mmol, 0.10 equiv), K₃PO₄ (433 mg,2.04 mmol, 3.99 equiv), 1,4-dioxane/H₂O (4/1 mL). The resulting solutionwas stirred for overnight at 100° C. in an oil bath. The resultingmixture was concentrated under vacuum. The residue was applied onto asilica gel column with dichloromethane/methanol (10:1). The resultingcrude product (100 mg) was purified by Prep-HPLC under the followingconditions (1#-Waters 2767-1): Column, SunFire Prep C18, 19*150 mm 5 um;mobile phase, water with 0.05% TFA and CH₃CN (48% CH₃CN up to 68% in 8min, up to 100% in 2 min); Detector, uv 220 254 nm. This resulted in 22mg (12%) of2-(4-cyanophenyl)-3-(isopropyl(methyl)amino)quinoxaline-6-carboxylicacid as a yellow solid.

LC-MS: (ES, m/z): 347 [M+H]⁺

¹H-NMR (300 MHz, DMSO, ppm) δ 13.242 (s, 1H), 8.276-8.273 (d, J=0.9 Hz,2H), 8.052-7.931 (m, 6H), 4.211-4.123 (m, 1H), 2.647 (s, 3H),1.060-1.038 (d, J=6.6 Hz, 6H).

EXAMPLE 873-(Isopropyl(methyl)amino)-2-(pyridin-4-yl)quinoxaline-6-carboxylic acid

Step 1. Methyl3-(isopropyl(methyl)amino)-2-(pyridin-4-yl)quinoxaline-6-carboxylate

Into a 10-mL sealed tube, was placed methyl2-chloro-3-(isopropyl(methyl)amino)quinoxaline-6-carboxylate (150 mg,0.51 mmol, 1.00 equiv), pyridin-4-ylboronic acid (124.5 mg, 1.02 mmol,1.99 equiv), Pd(PPh₃)₄ (59 mg, 0.05 mmol, 0.10 equiv), K₃PO₄ (433 mg,2.04 mmol), 1,4-dioxane (4 mL). The resulting solution was stirred forovernight at 50° C. in an oil bath under nitrogen atmosphere. Theresulting mixture was concentrated under vacuum. The residue waspurified by silica gel column chromatography with EA/PE (1:40). Thisresulted in 50 mg (29%) of methyl3-(isopropyl(methyl)amino)-2-(pyridin-4-yl)quinoxaline-6-carboxylate asa yellow solid.

LC-MS: (ES, m/z): 337 [M+H]⁺

Step 2.3-(isopropyl(methyl)amino)-2-(pyridin-4-yl)quinoxaline-6-carboxylic acid

Into a 10-mL sealed tube, was placed a solution of methyl3-(isopropyl(methyl)amino)-2-(pyridin-4-yl)quinoxaline-6-carboxylate (50mg, 0.15 mmol, 1.00 equiv) in methanol (15 mL), sodium hydroxide (30 mg,0.75 mmol, 5.04 equiv), water (2 mL). The resulting solution was stirredfor 2 hr at 50° C. in an oil bath. The resulting mixture wasconcentrated under vacuum and diluted with 20 mL of H₂O. The pH value ofthe aqueous solution was adjusted to 4-5 with hydrogen chloride (2mol/L). The resulting solids were collected by filtration. This resultedin 22 mg (44%) of3-(isopropyl(methyl)amino)-2-(pyridin-4-yl)quinoxaline-6-carboxylic acidas a yellow solid.

LC-MS: (ES, m/z): 323 [M+H]⁺

¹H-NMR (300 MHz, DMSO, ppm) δ 8.791-8.771 (d, J=6.0 Hz, 2H), 8.279-8.276(d, J=0.9 Hz, 1H), 8.007-7.938 (m, 2H), 7.870-7.849 (d, J=6.3 Hz, 2H),4.250-4.162 (m, 1H), 2.657 (s, 3H), 1.081-1.059 (d, J=6.6 Hz, 6H).

EXAMPLE 882-(H-Imidazo[1,2-a]pyridin-6-yl)-3-(isopropyl(methyl)amino)quinoxaline-6-carboxylicacid

Into a 10-mL sealed tube, was placed methyl2-chloro-3-(isopropyl(methyl)amino)quinoxaline-6-carboxylate (70 mg,0.24 mmol, 1.00 equiv), H-imidazo[1,2-a]pyridin-6-ylboronic acid (59 mg,0.36 mmol, 1.53 equiv), Pd(PPh₃)₄ (28 mg, 0.02 mmol, 0.10 equiv), K₃PO₄(200 mg, 0.94 mmol, 3.96 equiv), 1,4-dioxane/H₂O (4/1 mL). The resultingsolution was stirred for overnight at 100° C. in an oil bath. Theresulting mixture was concentrated under vacuum. The residue waspurified by silica gel column chromatography withdichloromethane/methanol (30:1). The resulting crude product (80 mg) waspurified by Prep-HPLC under the following conditions (1#-Waters 2767-5):Column, SunFire Prep C18, 19*150 mm 5 um; mobile phase, water with 0.05%TFA and CH₃CN (15% CH₃CN up to 37% in 9 min, up to 100% in 1 min, downto 15% in 1 min); Detector, uv 254 nm. This resulted in 26 mg (30%) of2-(H-imidazo[1,2-a]pyridin-6-yl)-3-(isopropyl(methyl)amino)quinoxaline-6-carboxylicacid as a yellow solid.

LC-MS: (ES, m/z): 362 [M+H]⁺

¹H-NMR (300 MHz, DMSO, ppm) δ 9.422 (s, 1H), 8.451 (s, 1H), 8.309 (s,1H), 8.273-8.250 (d, J=6.9 Hz, 1H), 8.145 (s, 1H), 8.041-7.998 (m, 3H),4.243-4.177 (m, 1H), 2.741 (s, 3H), 1.098-1.082 (d, J=4.8 Hz, 6H).

EXAMPLE 892-(Benzofuran-2-yl)-3-(isopropyl(methyl)amino)quinoxaline-6-carboxylicacid

Step 1. Methyl2-(benzofuran-2-yl)-3-(isopropyl(methyl)amino)quinoxaline-6-carboxylate

Into a 10-mL sealed tube, was placed methyl2-chloro-3-(isopropyl(methyl)amino)quinoxaline-6-carboxylate (200 mg,0.68 mmol, 1.00 equiv), benzofuran-2-ylboronic acid (220 mg, 1.36 mmol,1.99 equiv), Pd(PPh₃)₄ (157 mg, 0.14 mmol, 0.20 equiv), K₃PO₄ (577 mg,2.73 mmol, 4.01 equiv), 1,4-dioxane (4 mL). The resulting solution wasstirred for overnight at 100° C. in an oil bath. The resulting mixturewas concentrated under vacuum. The residue was applied onto a silica gelcolumn with ethyl acetate/petroleum ether (1:40). This resulted in 160mg (63%) of methyl2-(benzofuran-2-yl)-3-(isopropyl(methyl)amino)quinoxaline-6-carboxylateas a yellow solid.

LC-MS: (ES, m/z): 376 [M+H]⁺

Step 2.2-(Benzofuran-2-yl)-3-(isopropyl(methyl)amino)quinoxaline-6-carboxylicacid

Into a 50-mL round-bottom flask, was placed a solution of methyl2-(benzofuran-2-yl)-3-(isopropyl(methyl)amino)quinoxaline-6-carboxylate(160 mg, 0.43 mmol, 1.00 equiv) in methanol (20 mL), sodium hydroxide(85 mg, 2.12 mmol, 4.99 equiv), water (2 mL). The resulting solution wasstirred for 2 hs at 50° C. in an oil bath. The resulting mixture wasconcentrated under vacuum. The resulting solution was diluted with 20 mLof H₂O. The pH value of the aqueous solution was adjusted to 4-5 withhydrogen chloride (2.5 M). The resulting solids were collected byfiltration. The crude product (120 mg) was purified by Prep-HPLC withthe following conditions (1#-Waters 2767-1): Column, XbridgePrep ShieldRP 18, 5 um, 19*150 mm; mobile phase, water with 0.05% TFA and CH₃CN(58% CH₃CN up to 78% in 8 min, up to 100% in 2 min); Detector, UV 220254 nm. This resulted in 70 mg (45%) of2-(benzofuran-2-yl)-3-(isopropyl(methyl)amino)quinoxaline-6-carboxylicacid as a yellow solid.

LC-MS: (ES, m/z): 362 [M+H]⁺

¹H-NMR (300 MHz, DMSO, ppm) δ 13.250 (s, 1H), 8.275-8.272 (d, J=0.9 Hz,1H), 8.034-7.962 (m, 2H), 7.826-7.702 (m, 3H), 7.482-7.328 (m, 2H),4.254-4.167 (m, 1H), 2.836 (s, 3H), 1.180-1.158 (d, J=6.6 Hz, 6H).

The following compounds may generally be made via a modified version ofthe schemes shown.

EXAMPLE 90(S)-2-(4-Fluorophenyl)-3-(2-methyl-4-(pyridin-2-yl)piperazin-1-yl)quinoxaline-6-carboxylicacid

LC-MS: (ES, m/z): 444 [M+H].

EXAMPLE 91(S)-2-(4-Fluorophenyl)-3-(2-methylpiperidin-1-yl)quinoxaline-6-carboxylicacid

LC-MS: (ES, m/z): 366 [M+H].

EXAMPLE 923-(Cyclopropyl(methyl)amino)-2-(4-fluorophenyl)quinoxaline-6-carboxylicacid

LC-MS: (ES, m/z): 338 [M+H].

EXAMPLE 93(R)-2-(4-Fluorophenyl)-3-(2-(methoxymethyl)pyrrolidin-1-yl)quinoxaline-6-carboxylicacid

LC-MS: (ES, m/z): 382 [M+H].

EXAMPLE 94(S)-3-(2-Methyl-4-(pyridin-2-yl)piperazin-1-yl)-2-phenylquinoxaline-6-carboxylicacid

LC-MS: (ES, m/z): 426 [M+H].

EXAMPLE 952-(Benzo[d][1,3]dioxol-5-yl)-3-(3,4-dihydroquinolin-1(2H)-yl)quinoxaline-6-carboxylicacid

LC-MS: (ES, m/z): 426 [M+H].

¹H-NMR (300 MHz, CDCl₃): 8.70 (s, 1H), 8.22 (d, J=8.6 Hz, 1H), 8.11 (d,J=8.6 Hz, 1H), 7.32 (d, J=8.4 Hz, 1H), 7.29 (1H), 7.06 (m, 1H), 6.88 (m,1H), 6.86-6.67 (m, 4H), 5.95 (s, 2H), 3.87 (br t, 2H), 2.84 (br t, 2H),2.09 (br t, 2H).

EXAMPLE 963-(Octahydroquinolin-1(2H)-yl)-2-phenylquinoxaline-6-carboxylic acid

LC-MS: (ES, m/z): 388 [M+H].

EXAMPLE 973-(Isopropyl(methyl)amino)-2-(pyridin-3-yl)quinoxaline-6-carboxylic acid

LC-MS: (ES, m/z): 323 [M+H].

EXAMPLE 982-(Furan-2-yl)-3-(isopropyl(methyl)amino)quinoxaline-6-carboxylic acid

LC-MS: (ES, m/z): 312 [M+H].

EXAMPLE 993-(Isopropyl(methyl)amino)-2-(quinolin-3-yl)quinoxaline-6-carboxylicacid

LC-MS: (ES, m/z): 373 [M+H].

EXAMPLE 1003-(Isopropyl(methyl)amino)-2-(4-morpholinophenyl)quinoxaline-6-carboxylicacid

LC-MS: (ES, m/z): 407 [M+H].

EXAMPLE 1013-(1,1-Dioxidothiomorpholino)-2-(4-fluorophenyl)quinoxaline-6-carboxylicacid

LC-MS: (ES, m/z): 402 [M+H].

EXAMPLE 1023-(1,1-Dioxidothiomorpholino)-2-phenylquinoxaline-6-carboxylic acid

LC-MS: (ES, m/z): 384 [M+H].

EXAMPLE 1032-(4-Fluorophenyl)-3-(3-oxopiperazin-1-yl)quinoxaline-6-carboxylic acid

LC-MS: (ES, m/z): 367 [M+H].

EXAMPLE 104 2-(4-Fluorophenyl)-3-(methyl(piperidin-4-yl)amino)quinoxaline-6-carboxylic acid

LC-MS: (ES, m/z): 331 [M+H].

EXAMPLE 1052-(4-Fluorophenyl)-3-(methyl(tetrahydro-2H-pyran-4-yl)amino)quinoxaline-6-carboxylicacid

LC-MS: (ES, m/z): 382 [M+H].

EXAMPLE 1063-(Cyclopentyl(methyl)amino)-2-(4-fluorophenyl)quinoxaline-6-carboxylicacid

LC-MS: (ES, m/z): 366 [M+H].

EXAMPLE 1073-(Isopropyl(methyl)amino)-2-(5-methylthiophen-2-yl)quinoxaline-6-carboxylicacid

LC-MS: (ES, m/z): 342 [M+H].

EXAMPLE 1083-(Isopropyl(methyl)amino)-2-(thiophen-2-yl)quinoxaline-6-carboxylicacid

LC-MS: (ES, m/z): 328 [M+H].

EXAMPLE 1093-(Isopropyl(methyl)amino)-2-(6-methoxypyridin-3-yl)quinoxaline-6-carboxylicacid

LC-MS: (ES, m/z): 353 [M+H].

EXAMPLE 1102-(Furan-2-yl)-3-(isopropyl(methyl)amino)quinoxaline-6-carboxylic acid

LC-MS: (ES, m/z): 312 [M+H].

EXAMPLE 1112-(4-Fluorophenyl)-3-(4-(N-methylacetamido)piperidin-1-yl)quinoxaline-6-carboxylicacid

LC-MS: (ES, m/z): 423 [M+H].

EXAMPLE 1122-(4-Fluorophenyl)-3-(4-methyl-3-oxopiperazin-1-yl)quinoxaline-6-carboxylicacid

LC-MS: (ES, m/z): 381 [M+H].

EXAMPLE 1132-(1H-Indol-6-yl)-3-(isopropyl(methyl)amino)quinoxaline-6-carboxylicacid

LC-MS: (ES, m/z): 361[M+H].

EXAMPLE 1142-(1H-Indol-2-yl)-3-(isopropyl(methyl)amino)quinoxaline-6-carboxylicacid

LC-MS: (ES, m/z): 361[M+H].

The following compounds can generally be made using the methods known inthe art and described above. It is expected that these compounds whenmade will have activity similar to those that have been made in theexamples above.

-   2-phenyl-3-(2,3,4,5-tetrahydro-1H-benzo[b]azepin-1-yl)quinoxaline-6-carboxylic    acid-   2-(4-fluorophenyl)-3-(2,3,4,5-tetrahydro-1H-benzo[b]azepin-1-yl)quinoxaline-6-carboxylic    acid-   (S)-3-(sec-butyl(methyl)amino)-2-(4-fluorophenyl)quinoxaline-6-carboxylic    acid-   3-(sec-butyl(methyl)amino)-2-(furan-3-yl)quinoxaline-6-carboxylic    acid-   3-(isopropyl(methyl)amino)-2-(1H-pyrazol-4-yl)quinoxaline-6-carboxylic    acid-   3-(isopropyl(methyl)amino)-2-(6-methoxypyridin-3-yl)quinoxaline-6-carboxylic    acid-   2-(1H-indazol-6-yl)-3-(isopropyl(methyl)amino)quinoxaline-6-carboxylic    acid-   3-(isopropyl(methyl)amino)-2-(1-methyl-1H-indazol-6-yl)quinoxaline-6-carboxylic    acid-   2-(1-(tert-butoxycarbonyl)-1H-indol-2-yl)-3-(isopropyl(methyl)amino)quinoxaline-6-carboxylic    acid-   2-(1-(tert-butoxycarbonyl)-5-methoxy-1H-indol-2-yl)-3-(isopropyl(methyl)amino)    quinoxaline-6-carboxylic acid-   3-(isopropyl(methyl)amino)-2-(5-methoxy-1H-indol-2-yl)quinoxaline-6-carboxylic    acid-   2-(5-fluoro-1H-indol-2-yl)-3-(isopropyl(methyl)amino)quinoxaline-6-carboxylic    acid-   2-(5-bromopyridin-3-yl)-3-(isopropyl(methyl)amino)quinoxaline-6-carboxylic    acid-   2-(1H-indazol-5-yl)-3-(isopropyl(methyl)amino)quinoxaline-6-carboxylic    acid-   3-(isopropyl(methyl)amino)-2-(3-(trifluoromethyl)-1H-pyrazol-4-yl)quinoxaline-6-carboxylic    acid-   2-(6-(tert-butoxycarbonylamino)pyridin-3-yl)-3-(isopropyl(methyl)amino)quinoxaline-6-carboxylic    acid-   2-(5-fluoropyridin-2-yl)-3-(isopropyl(methyl)amino)quinoxaline-6-carboxylic    acid-   3-(isopropyl(methyl)amino)-2-(5-(trifluoromethyl)pyridin-2-yl)quinoxaline-6-carboxylic    acid-   3-(isopropyl(methyl)amino)-2-(6-(trifluoromethyl)pyridin-3-yl)quinoxaline-6-carboxylic    acid-   2-(5-cyanopyridin-2-yl)-3-(isopropyl(methyl)amino)quinoxaline-6-carboxylic    acid-   3-(isopropyl(methyl)amino)-2-(6-(pyrrolidin-1-yl)pyridin-3-yl)quinoxaline-6-carboxylic    acid-   2-(6-fluoropyridin-3-yl)-3-(isopropyl(methyl)amino)quinoxaline-6-carboxylic    acid-   (S)-2-(benzofuran-2-yl)-3-(2-methylpyrrolidin-1-yl)quinoxaline-6-carboxylic    acid-   2-(benzofuran-2-yl)-3-(cyclopropyl(methyl)amino)quinoxaline-6-carboxylic    acid-   2-(5-fluorobenzofuran-2-yl)-3-(isopropyl(methyl)amino)quinoxaline-6-carboxylic    acid-   2-(5-chlorobenzofuran-2-yl)-3-(isopropyl(methyl)amino)quinoxaline-6-carboxylic    acid-   2-(benzofuran-2-yl)-3-(sec-butyl(methyl)amino)quinoxaline-6-carboxylic    acid

The activity of the compounds in Examples 1-114 as PASK modulators isillustrated in the following assays. The other compounds listed above,which have not yet been made and/or tested, are predicted to haveactivity in these assays as well.

BIOCHEMICAL ASSAY FOR HPASK ACTIVITY

PAS Kinase Luminescence Assay

One assay for purified hPASK activity utilizes the Kinase-GloLuminescent Kinase Assay (Promega), which quantifies the amount of ATPremaining in solution following kinase reaction. The assay is carriedout in a 96-well plate format and is performed by adding a volume ofKinase-Glo Reagent (Promega, catalog #V3771) equal to the volume ofsolution in the well of a completed kinase reaction. Kinase-Glo reagentcontains Luciferase and its substrate. After addition to a kinasereaction it allows to measure luminescence. The amount of ATP left insolution at the time of Kinase-Glo Plus addition is directlyproportional to the luminescence that is measured in each well, andinversely correlated with kinase activity.

Purified hPASK from insect cells (0.02 μg) is added to a 50 μL reactionmix containing 40 mM HEPES (pH 7.0), 100 mM KCl, 5 mM MgCl₂, 1 mM DTTand 1 μg of MBP protein. Inhibitory compounds are then added and themixture is incubated for 10 min at 25° C. before adding 5 μL of ATP (atdesired concentration). The reaction is allowed to proceed at 25° C. for1 hour before adding 50 μL of Kinase-Glo reagent. The luminescence ismeasured as soon as 10 minutes after Kinase-Glo reagent is added.

Results are shown below in Table 1.

TABLE 1 IC₅₀ Kinase Domain +indicates ≦10 μm Example # −indicates ≧10 μm11 + 16 + 17 + 18 + 19 + 20 + 21 + 22 − 23 + 24 + 25 + 26 + 27 + 28 +29 + 30 + 31 +PASK ATP Radiochemical Assay

Purified PASK (UniProt #Q96RG2; human recombinant N-terminal GST taggedconstruct, residues 879-1323) from insect cells (final concentration 5nM) is added to freshly prepared Base Reaction Buffer containing 20 mMHEPES (pH 7.5), 10 mM MgCl₂, 1 mM EGTA, 0.02% Brij35, 0.02 mg/ml BSA,0.1 mM Na₃VO₄, 2 mM DTT, 1% DMSO and Myelin Basic Protein (20 μM final).Test compounds in DMSO are then added and the mixture, followed bydelivery of ³³P-ATP (specific activity 0.01 μCi/μl final) to initiatethe reaction. The kinase reaction is incubated for 120 min at roomtemperature. The entire reaction mixture is washed through onto a P81Phosphocellulose paper and washed three times for 10 minutes in 75 mMphosphoric acid and once in methanol prior to drying and scintillationcounting.

Results for this assay are shown below in Table 2. NT indicates that thecompound was not tested.

TABLE 2 IC₅₀ Kinase Domain +indicates ≦10 μm Example # −indicates ≧10 μm1 + 2 + 3 + 4 − 5 − 6 + 7 + 8 + 9 + 10 + 12 + 13 + 14 + 15 + 16 + 17 +18 + 19 + 20 + 21 + 22 NT 23 NT 24 + 25 NT 26 + 27 NT 28 − 29 − 30 +31 + 32 + 40 + 43 + 46 + 51 + 52 + 55 + 57 + 58 + 65 + 66 + 63 + 64 +72 + 74 + 75 + 76 + 77 + 78 + 79 + 80 + 81 + 83 + 84 + 87 + 88 + 89 +PAS Kinase FRET Assay

The aim of the FRET assay is to determine the inhibition potential oftest compounds on targeted kinase. This assay platform provides ahomogenous screening method for measuring kinase activity byquantitating the amount of phospho-substrate in solution following akinase reaction.

In the presence of kinase and ATP, the Ulight-peptide is phosphorylatedand captured by an anti-phospho-substrate antibody, which brings the Euchelate donor and Ulight acceptor dyes into close proximity. Uponexcitation at 340 nm, the Eu chelate transfers its energy to the Ulightdye, resulting in a fluorescent light emission at 665 nm.

Titration of kinase at 1 mM ATP was achieved via the following protocol.After making serial three-fold dilutions of PASK (Invitrogen) inreaction buffer across the plate; 5 μl of kinase dilution and 5 μlsubstrate/ATP mix were added to the wells of the white Optiplate-384(PerkinElmer). The contents of the plate were and incubated at RT for 1h. The reaction was stopped by adding 5 μl of stop solution to each testwell followed by mixing and incubation at RT for 10 minutes. 5 μl ofdetection mix (detection antibody diluted in detection buffer) wasadded; the contents of the plate were mixed and then incubated in thedark for 1 hour at RT. The signal was recorded at TR-FRET mode (665nm/615 nm). The results were graphed to calculate the EC₅₀.

Titration of ATP at the EC₅₀ concentration of kinase to determine ATPKm,app. was performed using the following method. After making serialdilutions of ATP (Invitrogen), 5 μl of ATP dilution and 5 μlsubstrate/kinase mix were added to the wells of the white Optiplate-384(PerkinElmer). The contents of the plate were and incubated at RT for 1h. The reaction was stopped by adding 5 μl of stop solution to each testwell followed by mixing and incubation at RT for 10 minutes. 5 μl ofdetection mix (detection antibody diluted in detection buffer) wasadded; the contents of the plate were mixed and then incubated in thedark for 1 hour at RT. The signal was recorded at TR-FRET mode (665nm/615 nm). The results were graphed to calculate the EC₅₀ as the ATPKm,app.

Compound screening was done via the following method. 10 mM stocksolution of test compound in DMSO was prepared by dissolving testcompound in DMSO at RT for 1 hour, and then sonicating at 100% outputfor 8 minutes. If compound is not soluble under this condition, it wasdiluted to 3 mM. Kinase reaction buffer was prepared containing 10 mMMgCl₂, 50 mM HEPES, 1 mM EGTA, 0.01% TWEEN-20, 2 mM DTT. Serialdilutions of the test compounds were prepared at 4× final assayconcentrations using Freedom EVO200® dispensing system as follows:12×10⁻⁵ M, 4×10⁻⁵ M, 1.33×10⁻⁵ M, 4.44×10⁻⁶ M, 1.48×10⁻⁶ M, 4.92×10⁻⁷ M,1.65×10⁻⁷ M, 5.48×10⁻⁷ M, 1.82×10⁻⁸M, 6.09×10⁻⁹, 2.03×10⁻⁹ M. Testcompounds (2.5 μl at 4× the final assay concentration) was added towells using Freedom EVO200® dispensing system. As a positive control,2.5 μl of positive compound was added to assay wells, and 2.5 μl of DMSOto assay wells as vehicle control. Kinase solution was prepared inreaction buffer at 2× final assay concentration. Kinase solution (5 μl)was added to each well of the assay plate. The substrate and ATPsolution was prepared in kinase reaction buffer at 4× final assayconcentration. The kinase reaction was started by adding 2.5 μl ofsubstrate+ATP mix solution to each well of the assay plate. The plate ismixed on a plate shaker; then covered and allowed to react for 2 hoursin the dark at 25° C. without shaking. The reaction was stopped byadding 5 μl of stop solution to each test well followed by mixing andincubation at RT for 10 minutes in the dark. 5 μl of detection mix(detection antibody diluted in detection buffer) was added; the contentsof the plate were mixed and then incubated in the dark for 1 hour at RT.The signal was recorded at TR-FRET mode (665 nm/615 nm).

Results are shown below in Table 3.

TABLE 3 IC₅₀ Kinase Domain +indicates ≦10 μm Example # −indicates ≧10 μm32 + 33 + 34 + 35 + 36 + 37 + 38 + 39 + 40 + 41 + 42 + 43 + 44 + 45 +46 + 47 + 48 + 49 + 50 + 51 + 52 + 53 + 54 + 55 + 56 + 57 + 58 + 65 +59 + 60 + 61 + 66 + 67 + 68 + 62 + 63 + 64 + 69 + 70 + 71 + 72 + 73 +74 + 75 + 76 + 77 + 78 + 79 + 80 + 81 + 82 − 83 + 84 + 85 + 86 + 87 +88 + 89 + 90 + 91 + 92 + 93 + 94 + 95 + 96 + 97 + 98 + 99 + 100 + 101 −102 − 103 + 104 + 105 + 106 + 107 + 108 + 111 + 112 +In Vivo Assays

A selected compound disclosed above (“Subject Compound”), Example 57,has been tested in two models of dyslipidemia. This compound, thought tobe a specific PASK inhibitor, was expected to reproduce importantphenotypic features of the PASK−/− mouse (31) in a mouse high fatdietary model and in a rat high fructose dietary model. All values givenbelow are averages over the treatment groups.

Mouse High Fat Dietary Model

A standard model of human hyperlipidemia and insulin resistance is themouse fed a high fat diet for several weeks (31, 33). Additionally,since hepatic lipid synthesis is known to be regulated by foodconsumption, the fast/re-feed cycle of Horton et al. (32) wasincorporated into the chronic high fat diet model. The compound wasevaluated in this model as an agent to restore insulin sensitivity andlower blood lipids. The chronic high fat diet was fed to mice tosimulate a standard Western diet which is elevated in calories from highfat and carbohydrate intake. This and similar models of dietary inducedobesity, insulin insensitivity and elevated serum lipids and cholesterolare used as mouse and rat models of human pathology includinghyperlipidemia, type II diabetes, atherosclerosis, obesity,cardiovascular and liver disease. These models have been used asexcellent predictors of efficacy in human clinical trials (PPAR and FXRagonists).

The farnesoid X receptor (FXR) is a ligand-activated transcriptionfactor and a member of the nuclear receptor superfamily. This receptorhas been shown to have crucial roles in controlling bile acidhomeostasis, lipoprotein and glucose metabolism, hepatic regeneration,intestinal bacterial growth and the response to hepatotoxins. WAY-362450is an agonist of the FXR and has been shown to reduce serumtriglycerides and cholesterol in several models of hyperlipidemia andprotects against the development of atherosclerotic plaque formation inmouse atherosclerosis models and liver inflammation and fibrosis in amurine model of non-alcoholic steatohepatitis (33, 34, 35, 36). Whilethe mechanism of action of FXR agonists is clearly distinct from PASKinhibition, WAY-362450 has been used as a positive control compoundproducing physiologically beneficial changes in glucose and lipidmetabolism resembling inhibition of PASK. Throughout these in vivoassays, WAY-362450 has been used as a control compound, and will bereferred to as such.

The study design is shown in Table 4.

TABLE 4 Dose Dose Level Concentration Group Test Article (mg/kg) (mg/mL)1 Vehicle 0 0 2 Subject 30 3 Compound 3 Subject 100 10 Compound 4Control 30 3

Male C57Bl6 mice were obtained from Jackson Laboratories and had beenfed a high fat diet (60% kcal fat) for eight weeks. The mice were fed anidentical high fat diet (Research Diet D12492) upon arrival and duringthe study. All mice were treated with the subject compound at 30 or 100mg/kg, control compound (WAY-362450) at 30 mg/kg or vehicle by oralgavage daily for three days. On the final day, 10 animals from eachgroup began an 24 hour fast and then were sacrificed (fasted groups 1a,2a, 3a, 4a). Alternatively, 10 animals from each group underwent a 24hour fast followed by a 12 hour re-feed period with the same high fatdiet ad libitum and then were sacrificed (re-fed groups 1b, 2b, 3b, 4b).

Body weights were monitored at the start and end of the protocol. Aftercompleting the fast or fast/re-feed conditions, the mice were givenavertin for anesthesia by intraperitoneal administration. Whole bloodwas collected by cardiac puncture and the mice were terminated bycervical dislocation. Livers were collected surgically, weighed andimmediately frozen in liquid nitrogen. The blood was placed inLi-heparin treated tubes, centrifuged to collect plasma and the plasmafrozen.

The plasma was analyzed by standard colorimetric assays for glucose,insulin, triglycerides and cholesterol. Frozen liver samples werepulverized and extracted in ethanolic KOH and analyzed for livertriglycerides and cholesterol.

After completing the dosing schedule and the fast/re-feed cycle, vehicletreated animals weighed 29.2 g. Treatment with the subject compound at30 mg/kg or 100 mg/kg reduced body weight in a dose dependent manner by2.7% and 5.1%, respectively. The control compound (WAY-362450) at 30mg/kg also reduced body weight by 6.5% as compared to the Vehicle withFast/Re-feed group. Additionally, vehicle treated mice which were fastedonly (no re-feed) weighed 27.3 g at the completion of the study. Thesubject compound also decreased body weight in fasted only animals by1.8% and 5.1%, similar to the dose responsive reduction in body weightin the fasted and re-fed animals. The control compound decreased bodyweight in the fasted only animals by 4% compared to the Vehicle Fastedgroup.

Liver weights were measured in mice that were treated with vehicle, thesubject compound or the control compound and fasted or fasted andre-fed. Vehicle treated mice that were fasted and re-fed displayed meanterminal liver weights of 1.2 g and 0.9 g for fast/re-feed and fastedonly mice, respectively. The subject compound at 30 and 100 mg/kg causeda trend of dose dependent reductions in liver weights of about 7-9%. Theeffects of the control compound treatment at 30 mg/kg on liver weightwere identical to those of the subject compound at the same dose.

The subject compound also caused dose related reductions in plasmaglucose and insulin levels compared to vehicle treated mice in both thefasted and re-fed groups. These effects were similar or greater thanthose produced by treatment with the control compound. Vehicle micewhich underwent the complete fast and re-feed cycle exhibited plasmaglucose levels of 104 mg/dl and the subject compound decreased glucoseby up to 21% at the highest dose (100 mg/kg). The control compoundincreased plasma glucose by 7.6%. In the fasted only mice, vehicletreated mice displayed a mean circulating plasma glucose concentrationof 116 mg/dl and the subject compound decreased glucose by 30% and 43%in a dose related manner. The control compound caused a 19% reduction infasted mice. Plasma insulin concentrations were decreased by treatmentwith the subject compound dose dependently (10% and 28% at 30 and 100mg/kg) in the fasted and re-fed mice compared to vehicle controls (2.32μIU/ml). Insulin was also reduced in the control compound treated micewhich underwent the fast and re-feed cycle by 22% compared to vehiclemice. In the fasted only mice, final plasma insulin concentrations were2.12 μIU/ml and this control level was decreased by up to 26% by thesubject compound (30 and 100 mg/kg) and 39% by the control compound (30mg/kg).

In the high fat fed mouse model, the subject compound dosed orally at 30and 100 mg/kg per day for three days caused a dose-related reduction inbody weight in the fasted and re-fed states. Additionally, the PASKinhibitor induced a concentration dependent decrease in liver weights inthe fasted state with a similar trend in the re-fed state. These changesin body and liver weights were similar or equivalent to those producedby exposure to the control compound. Moreover, the subject compoundtreatment produced dose-dependent decreases in plasma glucose andinsulin levels. These effects were noted in the fasted and re-fed statesand were comparable or greater than that caused by the control compoundexposure. Reductions in body weight, liver weight, plasma glucose andinsulin concentrations are indicative of insulin resensitization andutility in correcting the phenotype of type II diabetes.

Rat High Fructose Model with Fast/Re-Feed

Another standard model of human hyperlipidemia and insulin resistance isthe rat fed a high fructose diet for several weeks (33). Additionally,since hepatic lipid synthesis is known to be regulated by foodconsumption, the fast/reefed cycle of Horton et al. (32) wasincorporated into the chronic high fructose diet model. A compounddisclosed above was evaluated in this model as an agent to restoreinsulin sensitivity and lower blood lipids.

The study design is shown in Table 5.

TABLE 5 Dose Dose Test Level Concentration Group Article (mg/kg) (mg/mL)1 Vehicle 0 0 2 Subject 30 3 Compound 3 Subject 100 10 Compound 4Control 30 3

Eight week old male Sprague Dawley rats were purchased from Harlan, Inc.The rats weighed 200-225 g upon arrival and were divided into groups asdetailed in Table 2 and were immediately placed on a high fructose diet(60% kcal fructose; Open Source Diet #D00111301) ad libitum for threeweeks. During the last week of feeding the high fructose diet, the ratswere dosed with vehicle (5% solutol, 8% β cyclo-dextrin), subjectcompound at 30 mg/kg or 100 mg/kg or the control compound at 30 mg/kg byoral gavage once daily for 7 days. On the final day, all animals wereplaced on a 12 fast followed by a 12 hour re-feed period on the highfructose diet ad libitum.

Body weights were monitored throughout the protocol. After completingthe fast or fast/re-feed conditions, the rats were given avertin foranesthesia by intraperitoneal administration. Whole blood was collectedby cardiac puncture and the rats were terminated by cervicaldislocation. Livers were collected surgically, weighed and immediatelyfrozen in liquid nitrogen. The blood was placed in Li-heparin treatedtubes, centrifuged to collect plasma and the plasma frozen.

The plasma was analyzed by standard colorimetric assays for glucose,insulin, triglycerides and cholesterol.

As seen in FIG. 1, there was a significant increase in body weight ofthe control compound treated group compared to the Vehicle control groupover the course of the drug treatment period of 7 days. Rats treatedwith the subject compound at 30 mg/kg displayed a modest increase inbody weight relative to the Vehicle group. and animals treated with thesubject compound at 100 mg/kg exhibited a modest decrease in body weightrelative to the Vehicle group.

Liver weights from the high fructose diet rats treated with the subjectcompound and the control compound were measured. There was a smallincrease in liver weight in the control compound treated rats of about 2g, and only a slight trend of a dose related reduction in liver weightsin the subject compound treated rats. The maximal reduction in liverweight observed at the 100 mg/kg dose of the subject compound in the rathigh fructose model was about 4%. On the other hand, the controlcompound increased liver weights in these animals by about 15%.

The subject compound also caused dose related reductions in plasmaglucose and insulin levels compared to vehicle treated rats. Theseeffects were similar or greater than those produced by treatment withthe control compound. Vehicle treated rats on the high fructose dietdisplayed mean plasma glucose and insulin concentrations of 205 mg/dland 42.1 μIU/ml after the fast and re-feed cycle. Rats exposed to thesubject compound for 7 days showed a decrease in plasma glucose of 21.5%and 26.3% in 30 and 100 mg/kg treated groups, respectively, compared tovehicle. The control compound did not alter plasma glucoseconcentrations. Insulin levels were reduced by 15.4% and 31.4% bysubject compound exposure while the control compound rat insulin levelswere decreased by 63.2%.

Subject compound treatment caused a clear dose-dependent reduction inplasma triglycerides and a slight trend to reduce plasma cholesterol ascompared to vehicle control rats. Triglyceride and cholesterol levels inthe vehicle rats fed the high fructose diet with fast and re-feed were387 mg/dl and 69 mg/dl, respectively. The subject compound caused a25.1% reduction in triglycerides in the 30 mg/kg group and a 54.3%reduction in the 100 mg/kg group. The control compound also decreasedplasma triglycerides by 68% as compared to vehicle rats. Cholesterolconcentrations were decreased by 5.7 and 10% in the subjectcompound-treated rats with 30 and 100 mg/kg treatment. However, thecontrol compound increased plasma cholesterol by 17% with 30 mg/kgtreatment.

The subject compound dosed orally at 30 and 100 mg/kg per day for sevendays caused a dose-related reduction in body weight in the rats fed ahigh fructose diet with fast/re-feed. Additionally, the PASK inhibitorinduced a slight trend for a concentration dependent decrease in liverweights in the rats. The control compound treatment caused an increasein body weight and liver weight in this model. The subject compoundtreatment produced dose-dependent decreases in plasma glucose andinsulin levels. The subject compound greatly reduced plasma triglycerideconcentrations and slightly reduced plasma cholesterol levels in adose-related fashion in high fructose fed rats. All of these metaboliceffects of the subject compound were comparable or greater than thosecaused by the control compound exposure. Reductions in body weight,liver weight, plasma glucose and insulin concentrations are indicativeof insulin resensitization and utility in correcting the phenotype oftype II diabetes. The dose related decreases in plasma triglycerides andcholesterol suggest an anti-hyperlipidemic profile.

From the foregoing description, one skilled in the art can easilyascertain the essential characteristics of this invention, and withoutdeparting from the spirit and scope thereof, can make various changesand modifications of the invention to adapt it to various usages andconditions.

What is claimed is:
 1. A method of treatment of a metabolic diseasecomprising the administration of a therapeutically effective amount of acompound of structural Formula I:

or a pharmaceutically acceptable salt, or ester thereof, wherein: X₁ andX₂ are each N; R₁ and R₂ are each independently selected from the groupconsisting of alkyl, cycloalkyl, heterocycloalkyl, aryl, heteroaryl, andNR₅R₆, any of which may be optionally substituted, with the proviso thatat least one of R₁ or R₂ is NR₅R₆; R₃ is hydrogen; R₄ is selected fromthe group consisting of COOR₇, CONR₈R₉, CONR₁₀OR₁₁, and tetrazolyl; R₅and R₆ are each independently selected from the group consisting ofhydrogen, C₁-C₆ alkyl, C₁-C₆ alkenyl, C₁-C₆ alkynyl, C₁-C₇ cycloalkyl,C₁-C₇ heterocycloalkyl, aryl, heteroaryl, aralkyl, and heteroaralkyl,any of which may be optionally substituted; or taken together, R₅ and R₆may form a heterocycloalkyl or heteroaryl, either of which may beoptionally substituted; R₇, R₈, R₉, R₁₀, and R₁₁ are each independentlyselected from the group consisting of hydrogen, C₁-C₆ alkyl, aryl,heteroaryl, aralkyl and heteroaralkyl, any of which may be optionallysubstituted; R₁₈ and R₁₉ are independently selected from the groupconsisting of cycloalkyl, heterocycloalkyl, aryl, and heteroaryl, any ofwhich may be optionally substituted; and m and n are each independentlyan integer from 0 to 2, to a patient in need of treatment for ametabolic disease.
 2. The method of treatment of claim 1, wherein saidmetabolic disease is selected from the group consisting of metabolicsyndrome, diabetes, dyslipidemia, fatty liver disease, non-alcoholicsteatohepatitis, obesity, and insulin resistance.
 3. The method oftreatment of claim 2, wherein said diabetes is Type II diabetes.
 4. Themethod of treatment of claim 2, wherein said dyslipidemia ishyperlipidemia.